From my experience, you won't miss out at all! I found that during freshers there were always events going on that didn't include alcohol or going out. During my fresher's week, they held arts and crafts evenings, board game nights and film nights which were very popular! Even though the stereotype is for students to go out almost every night of freshers, in reality, for most people this is not the case so lots of people get involved with the non-alcohol-based events. There will also be lots of societies in freshers and throughout the year that host events that don't revolve around going out. Maybe take a look at the societies your uni offers to see if there are any you may be interested in!
I hope this helps, good luck at uni!
Florence (Lancaster University student ambassador)