This is a difficult topic to write about, @ubani1. You did well with it. It is told respectfully. The only actual judgment we see about Sarah's weight and size are her own. Body weight, health and self-image are things many people struggle with. Your story provides a sensitive view into the inner world of a person who does not feel she is okay as she is. I really liked the fact that the mother encourages, loves and accepts her.
One grammatical thing I will share with you is that the contractions "I'm" and "you're" are only used in certain contexts. It's odd, because "I'm" does mean the same thing as "I am" but they are not interchangeable. Same with "you're" and "you are."
In these instances, "I'm" should be "I am":
I couldn't handle the thought of leaving, and meeting new people, will they accept the way I'm or maybe they won't.
Sometimes I share this thought with my mother and she would make me realize how beautiful I'm from the inside because she understood me.
Here, "you're" should be changed to "you are":
And you should know you are beautiful just the way you're, baby you don't have to change anything or to please anyone, but the world can change its heart and see the real you.
In this excerpt, the first "you're" is correct, but the second one should be "you are."
So, my dear, you're beautiful just the way you're."
This one should also be "you are":
Then I said to myself, "You're beautiful just the way you're. You can do this."
There's an explanation of the rule here, but it's not a great explanation. If I can find a better one, I will provide it. I hope this helps!