I am trying to show my feelings fortowards them but my younger sister finds it cheesy. I am trying to show my feelings towards them but my younger sister finds it cheesy.

I am leaningdependent on them. I am dependent on them.

"Leaning" would be used in a more literal context (i.e. leaning on a table for support); depending/being dependent sounds more natural.

Most of the time, I feel like the youngest one atin the homuse. Most of the time, I feel like the youngest one in the house.

For some reason, "in the house" is used more often in this situation than "at home".

Our age gap isn't far small. Our age gap is small.

My grandma didoesn't remember us well, and she thinks our younger brother is ourthe oldest. My grandma doesn't remember us well, and she thinks our younger brother is the oldest.

Verb tense correction; didn't ----> past tense / doesn't -----> present tense (same as "thinks").

My grandma didoesn't remember us well, and she thinks our younger brother is ourthe oldest. My grandma doesn't remember well, and she thinks our younger brother is the oldest.

She is a lawyer, now. She is a lawyer now.

Comma isn't necessary because it's a short sentence.

She still, she haves to deal with her internship but her university part is closed for her. She still has to deal with her internship but her university is closed.

She didn't want to be lawyer at first but we convinced her to be lawyerone. She didn't want to be lawyer at first but we convinced her to be one.

This is a stylistic correction; removing "lawyer" at the end of the sentence lets it not be as repetitive.

I am jeaolous about this, because I lost my interest toin my major. I am jealous about this because I lost my interest in my major.

Inserted "because" to make the transition smoother.

EvBack then, I had enrolled toin architecture with strong passion, [but now I'm not as passionate anymore]. Back then, I had enrolled in architecture with strong passion, [but now I'm not as passionate anymore].

I'm not quite sure what this sentence is supposed to say. Hopefully my correction still portrayed the original meaning. Let me know if you need further clarification with this part