Or in You are my Frog King (Ben 10 inspiration) she is just Sarah Tennyson.

Name: Sarah Jensen-Tennyson (has a middle name but it's part of my real name, so no)

Age: (in You are my Frog King) 23 (in The Forgotten Hero) 10, 15
Main series: Sarah J10, Super hero Family, 12-26

Birthday: March 31st 1997

Powers: she has a alien device called the omnitrix to change whatever powered alien hero. Her omnitrix has samples of dna of aliens which helps her turn into the aliens. But it runs on energy which causes the omnitrix to wear out and needs to recharge again.

Friends: (Forgotten Hero) Rigby, Joker (Arthur), Wonder Woman (Dianna), Batman (Bruce Wayne), BumbleBee (Karen), Terra, The Hacker (real name is process)
(You are my Frog King) Dr Olysses, Thomas (the billionaire)...

Bio: not much to mention about her, her parents have superpowers by their dentist that went through their kid's dna, sadly Sarah never found her actual powers so she finds an omnitrix later. But it runs by her feelings, which was inspired by Starfire from Teen Titans

Looks (Anime)

(You are my Frog King)

Her in Ben 10 universe

Name: Sarah J-Tennyson

Age: 8 (classic), 14 (Ultimate Alien and Omniverse)

Powers: Omnitrix same genre (runs on how she feels), anodite (sky blue)

Crush/Lover: Dr Animo

Personality: shy, feels weak, scared of clowns since she was 12, but before she wasn't. Loves animals, monkeys and frogs are her personal favorite. Somehow is able to understand animals.