Is your grandmother rich ?
It's all about the money. Isn't it ?
Your aunt is doing her best to discredit your family.
She hopes that if your grandma thinks yours are a family of
thieves.. grandma will not give your family anything when she
dies....
Less for you and your family.. more for your aunt and her
family.
That's how a lot of family feud started.
But .. if your grandma is poor.. got nothing to her name.. in
poor health and needs to be taken care of... rest assured.. your
aunt will be the first to disappear.
So don't take it too personaly how your aunt treat you. It's all
part of her plan to cut you out. No matter what you do.. she's out
to get you.
Being poor and bad at your work/studies just makes it easier for
your aunt to stab you in the back.