It maybe doesn't need to be all or nothing right now - you're away from home so there's no real urgency about cutting them off and you may find that distance comes quite naturally as you build a life for yourself.
I found I really needed to distance myself from my parents and most of my siblings while I was in therapy processing the impact of their abuse. I started to have a bit more contact with them (i.e. 3/4 times a year instead of 1/2 times so no great, emotional reunion) and found I could just about tolerate that.
Recently I've found I can't be around them and stay healthy so I've withdrawn again and will go back to very limited contact. I've not cut off all contact because there are siblings I'm close to and would like some form of family relationship as I/they get older. I did at one point strongly feel I never wanted anything to do with them and but just never quite pulled away completely.
So, the reason I say does it need to be all or nothing right now isn't because they're family - my closest friends are my family and I love them dearly - it's because feelings can change, a lot. You're in a huge time of transition, becoming very aware of what you missed out on and feeling quite raw by the sounds of it. Work through your feelings, let yourself settling into a routine at uni and see how you feel. You may decide you want to cut them loose, you may not but once you decide to go no contact it's much harder to invite them back into your life if you change your mind - and as unlikely as it feels just now, you might.
In the meantime you can keep minimal contact - it's a busy time, arrange vacations with friends, don't have time to talk etc. You can choose the extent to which you have contact with them.