Okay so in this story Adrien mom doesn't die for a while. This is before/after the death in the show.
Adrien and Marinette are 6 years old when they first meet.
Let's start the story.

One day Mrs. Agreste decided that she wanted to get some bread. "Bye hon I will be right back. I am gonna go get some bread from the bakery."
"Okay hon see you soon." Said Mr. Argeste
Mrs. Agreste started to head out when little Adrien walks up to his mom."Mommy can I go with you?" Adrien asked
"Of course son I would love the company." So they head off to  the  bakery. When they get there, there is a  little girl who is around Adrien's age sitting on the counter hugging a stuffed ladybug and a young woman behind the counter. The little girl is wearing a yellow dress and her hair are in little buns. *bell rings* "Oh my well hello there and welcome to the Dupain- Chang's bakery. How may I help you?" Said the young woman behind the counter.
"I would like a loaf of bread please." Said Mrs. Agreste
"What kind of bread would like?"
"I would like baguette please."
"Yes, of course I will be right back." The woman left to wrap up the bread. While she was gone Adrien and the little girl stairs at each other like this.

Just then Adrien tries to make a conversation with the girl. "H-hi." Said Adrien weakly
"Hi, I am Marinette. What is your name?"
"Adrien. Adrien Agreste." Just then the woman walked back in. "There you go and what is your name so I know for future references?"
"Emily Agreste."
"Well then my name is Sabine Dupain- Chang."
Mrs. Agreste pays for the bread and get ready to leave.  "Well then, bye."
"Bye come back anytime."
"We will."
As Emily and Adrien start to leave Adrien and Marinette asked their parents. "Can we play together soon."
Emily looks up from Adrien then looks over at Sabine. They both says "Yes, you can."
Adrien and Marinette start to squill at the same time. It was so loud that the parents had to cover their ears. When the kids were done screaming Adrien and his mother walking out of the bakery. Adrien smiled because now he had a new friend who was his age that he play with, and Marinette feels the same way about him as he does with her. They both can't wait to play with each other and get to know each other better.
When Adrien and his mom gets home they are confronted by Mr. Argeste "So, how was it at the bakery."
"Good Adrien made a new friend and they both want to have a playdate together sometime."
"Well that's good news then."
They spent the next few hours together eating until it was time for bed. When it was time to go to bed it took Adrien a while to fall asleep because he couldn't stop thinking about his new friend.

Well that's all for now stay tuned for the next part. I know that it was really short but hopefully next part will be longer than this part. Next part will be coming soon, Bye for now.