The first port of call is to talk to them and explain how you feel; it's possible that they don't even realise that they're still treating you like a child when you're clearly above that.
If that doesn't go as planned, honestly I'd suggest letting them do as they please. If you were a teenager, yes maybe you're giving them serious cause to be worried if you go home late, but you're a 25 year old adult. Your safety is your own problem, and if they're getting worried about you and are losing sleep, well that's their problem too, isn't it? Don't feel guilty or stressed because they are making silly decisions entirely of their own accord.