how can being independent such as buying groceries and doing laundry make u proud? (as an high schooler)?

Answer 1

Doing adult activities shows you are maturing. Most kids take on more duties as they age and more if they have a single parent.

Answer 2

You would be surprised how many people cannot do these things on their own.
So if you are capable of buying groceries and doing laundry not just once in a while, but all the time, you are learning to be a mature and responsable adult. That should make you proud
and make you want to continue doing other things for yourself.
Practice makes perfect.