My life is so dull

I’m on summer holidays and I’m going into yr13.
I’ve barely been out of the house since summer started, solely because as a family we haven’t been anywhere and my parents are too strict for me to go out to meet anyone or even to go on a simple walk.
I feel like I’m loosing my mind at home. I have school work to do, I know, I’ve been doing it. It’s the only thing that can get my mind off the dullness of summer.
I’m a straight A* student so it’s not like I have an extreme amount to of work to do, though I’ve been pre reading stuff.
I just fear that I’m working so hard for absolutely nothing. Will life always be like this? My sister who is older than me (she’s 23), has a degree and a job and everything and still lives at home. My parents are only a little bit more lenient with her solely because she has a boyfriend and she’ll be safe with him. Even then though, my parents still dislike it when she goes out and she probably goes out to see her mates once every week.
I’m terrified that my life will be like hers. My sister doesn’t complain because she likes to stay at home anyway. But I do care. I want to have fun.
I’ve worked so hard at school so I can have a life which I am happy with and I am more free.
I just fear that I won’t get that.
This is why I’m looking forward to university ever so much, and I loathe whenever my parents suggest me going to a local uni so that I can stay at home so it won’t be ‘as costly’. I want to have freedom at university. I want to go out without my parents knowing, even if I am a girl.
I just yeah