How long is a piece of string?! It depends on many factors! To an extent, how you are now may well largely influence how you find it, if you are outgoing and sociable you will probably have a great time, if you are shy it may be a struggle. However, it will partly depend on who you end up with.
I think the main thing to be 'prepared for' is the 'full on ness' potentially of the whole experience. At the moment, you will obviously socialise at college and in evenings/weekends but go home at night. At Uni, other people are around all the time unless you lock yourself in your room (obviously you will do this when you are asleep/in your bathroom ) -not recommended if you want to make friends! If you like your own space, this can feel overwhelming and it may feel like you are in the 'Big Brother House' - but if I could offer myself advice (I am in my late 30s and Uni was a struggle socially for me) just go with it, enjoy it and accept you will never quite get such a social opportunity again! (by 2nd year you will be in houses and already it will get more insular.)
PS don't worry about what your current friends are doing, live YOUR life!