It mainly depends on the way you used to live with your parents. If you've always been independent, using your home like an hotel, you can live like this as long as you like it.
If you are doing long study, it might be difficult to get off before 25. From my experience I got lucky by having been paid to finish my study and then jumping on a phd financement. But I know of friends less lucky and still at their parents, it doesn't make them more stupid.
Also as long as you have good friends with their own house, you can party there and get the laundry done by your mother... Sounds like being in the army except you got to keep your two arms.