How much internet use is okay?

I turned 15 and my parents have given me an Internet lock that has existed since my first laptop. Half an hour during the week and one hour on weekends, between 1 p.m. And 6 p.m. And only on pages permitted by a whitelist. So I can't see any pictures on Whatsapp, receive voice messages, see stories because the Whatsapp server is unknown?!
Half an hour is of course quickly used up, my father allows me a little more internet when I have to prepare lectures. My parents don't have any mobile data, and of course I can't buy it.
I also have to say that I have never been on the cell phone for a long time, so it can't be the case that I would be on the cell phone too often too long.
My father justifies the whole thing with the fact that he would like to know where I'm going because I'm too young. It will be very difficult to change your mind.
What do you think about that?

I think that's very blatant. You are 15… Talk to the youth welfare office that this check is not okay at all.

I agree. That is absolutely correct. I also find it strange that you control it so strictly these days…

It's actually your own freedom. Of course you shouldn't surf in excess (like me haha about 8 hours) but two hours maximum are actually ok.

Of course it also depends on your grades. That means if you are not good at school your parents' decision is well founded. But with me my grandma often takes my cell phone away, even though I keep on writing and writing. And when I have exams, I always hang in my room for hours and only learn and touch the cell phone every few hours.

And maybe it is also due to your age or you have done something with which you have broken their trust

Sorry! Didn't read that you were 15