I was 19 when I moved in with my then DP. It was lovely and we lasted a good six years, and I had a lovely time, but I did miss out on Uni things and in hindsight (I'm 25 now) I do wish we had waited. I would think the same even if we were still together. You don't get that time again and waiting two years to move in together isn't a big deal - think of the money you'll save!
If you wanted, you could agree to set up a joint account and pay in a monthly amount that resembles monthly rent for your area. By the time you graduate, you'll have a nice deposit saved for a house or a nice wedding fund
honestly, that's what I would do if I had my time again.