Name - Greenkit - Greenpaw - Bravefeather.

Reasoning - She was named Greenkit and paw after her light green colored eyes(Did her parents just wait a few moons for her to open her eyes and the pigment to appear to name her?), when she got her full name, she became Bravefeather, Brave for how many lives and cats she saved,(I went through the whole backstory and it seems like she saved maybe two cats lives? And that was after she got her name. Who's lives did she save that it warrants a name change?) and feather after her brother Kestrelfeather who died soon after he became a full warrior.(Well naming her after her brother who she failed to save is a bit cruel on StarClan's part)

Age - 63 moons(at death?)

Gender - She-cat

Personality- witty, wise, a cat who would take a joke seriously, especially when it comes to some cat being hurt, moody at times, fancies the paws more than warriors and kits because of their unique questions.(Pretty good, though, based on the backstory, I would add 'eager to learn')

Appearance- A white she-cat with light gray blotches over her whole body, face to tail, inside those gray blotches are dark gray stripes of three to four.(It is impossible for her to be a tabby seeing as neither of her parents are) She has slightly curled ears and tail(Curled tails are recessive, meaning bother her parents would have to have it. The ears are fine, those are dominant). Her nose is light pink along with the color of her paw pads. She has light green colored eyes. She has somewhat think(not sure if you mean thick) medium-length fur(Recessive trait, short is dominant) and the fur on her muzzle is slightly long and curving downward.

Windclan - Starclan

Medicine cat

Mother: Silverdrop - A white-colored she-cat with blotches of silver(Actually, she'd realistically be silver with about level 4/level 5 white spotting), she has dark blue eyes and medium-length thick fur. Her nose is light pink and she has light pink paw pads. She has a scar atop her head from an owl in her younger days (recently made warrior), and she has a dark gray dot planted on her right leg(I'm pretty sure a cat can't be silver with a single dark gray spots)

Father: Stonestep - A muscular dark gray tom with short fur. He has slightly curled ears and a tail with a black nose. He has black paw pads and a very slim body. His eyes are light green and his back left leg has a couple of small scars and bites marks.(Nothing to remark on here)

Brother: Kestrelfeather - A silver-colored tom with short fur, he has a black colored nose and paw pads, his tail and ears are slightly curled and he has light green colored eyes. He has a slim lengthy body.(Nothing to remark on here)

Brother: Feathershine- A white and silver tom(It'd be silver with white spotting) with medium thick fur, he has dark blue colored eyes(I'm no expert, but in this instance, green eyes would be dominant and blue recessive, meaning all the kits would have green eyes) and a light pink colored nose and paw pads. He has a small but noticeable scar on his lip and above his right eye. He has a slim body and a dark grey spot on his right leg.(Again, pretty sure it can't be silver and gray, plus I'm pretty sure a marking as specific as this can't be passed down)

Mate - none

Kits - Hollowkit (Hollowpaw - Hollowgaze) A slim brown-furred tom with dull yellow eyes and a black nose, paw pads, and inside of his ears.(Him and Cypressmoon are siblings, right? Why do they look so different?)

Cypresskit (Cypresspaw, Cypressmoon) A tom with a black overcoat colored fur(what does a 'black overcoat colored fur' even mean) and a white underbelly, his fur is short and he has a plump round body. He has dull yellow eyes and a black nose, inside of ears, and paw pads.

As kit, she would always feel sick to her stomach when she watched apprentices and warriors practice battle moves on each other.(So she dislikes violence? I assume she's fine with blood, though)
Her brothers would tease her in a friendly way that would just make her bristle.
Instead of warrior activities, Greenkit was drawn to herbs and healing, she would always sneak out whenever her mother, Silverdrop, wasn't looking to go and see the medicine cat, Acornfang.(Does her mother not approve of medicine cats?)
He would always make funny jokes and overall make herbs fun to learn for Greenkit.
Soon, the time came when she was made a paw with her brothers, she was made medicine cat apprentice under Starclan's word as Acornfang had asked Starclan.
She learned every day, keen on everything and remembering what herbs did what, and where they grew.
She had kept doing this, occasionally healing some small injuries and aches.
When she was near ready to become a full medicine cat, her two brothers had become full warriors, being named Kestrelfeather and Feathershine.
She would help a Queen, Smokeleap, give birth to two kits.
Smokeleap would die from being too old as the two kits squirmed on the ground.(She died of old age the moment after she gave birth? Wouldn't that be counted as overexertion or just dying from the birth?)
Greenpaw saved them very quickly, licking their fur backward trying to get their blood flowing.
No Queens were in the nursery at the time as Smokeleap was the only one.(Sucks for the kits since they will die without milk. They shouldn't have survived to adulthood)
The clan agreed that the two kits should have been looked after in the medicine cats' den. Greenpaw would look after them during leaf-fall and leaf-bare.
Near the end of leaf-bare Greenpaw and Acornfang left the camp in search of burdock leaves and other types of herbs.
She and Acornfang had been stuck in an abandoned fox den under the roots of a tree from a raging blizzard.
Acornfang had kept her warm for the first hour before he had started becoming numb.
Before Acornfang died from the coldness, he choked out the words(That must have been a pretty long blizzard considering it takes 3-4 days of consistent freezing temperatures for a cat to die of hypothermia.) "Take care of Hollowkit and Cypresskit," the blizzard had soonly cleared and the leader sent out a patrol to find them, Greenpaw had told them he died saving her life from the raging blizzard
They left for camp and went on, she had learned enough about herbs that she reluctantly accepted her full medicine cat name Bravefeather, she had gotten it half a moon early than most medicine cats and felt slightly pressured.(When medicine cats get their full name actually depends on their mentor, so there's not set time period)
As time went on, she kept watch on Hollowkit and Cypresskit who had recently become paws.
One day, her two brothers came back from a patrol with some other warriors, bleeding out and injured.(Damn, a patrol made them bleed out? Thats some agressive clans)
She had tried and healed some and most warriors, Kestrelfeather and Ripplelight had died from too much blood loss.(Wait, if her brother died after she got her full name, then why was she named after him?)
Over time Bravefeather had gotten depressed, she would barely leave her duties or go out of camp, only if necessary.
The leader, Sorrelstar, had given her an apprentice called Dewpaw.
This made her get out more and teach him what she knew.
She had given Dewpaw the name Dewlight, after Ripplelight who she had tried to save.(This clan likes immortalizing dead cats)
Time went on and she had grown old.
She never retired and one day died in her sleep, old age finally putting a stop to her life.
She went to Starclan young and relaxed.

Extra -

A quote that she had said to Dewpaw, as he complained about doing the elders ticks...
"Elders are not ones to want to be stuck in a den all day, their bodies are old but their minds and hearts are as young as yours Dewpaw. Their hearts tell them to roam the plains and do warrior stuff that they did in their younger days,"(Interesting, but I don't see what this has to do with removing ticks?It'd probably fit better if Dewpaw was complaining about taking care of the elders in general, or 'wasting' herbs on them)

Pretty good OC, just a few things to change and to answer

8/10