What should you know before moving in with a SO?

My boyfriend and I are 21 and graduating college! We've been together for a year and a half decided to move in together after graduation. Originally we were going to have a 4-5 person house and each of us having or own room to make it more of a housemate situation, but because of other people's life events it's down to just him and I staying in this city now. Because of the cost of rent here it's unlikely that we will find a place in our budget that allows us each to have our own room and the thought of jumping into a one bedroom situation is freaking me out a bit.

What are some things we should be discussing before we do this? We understand that rent and utilities are going to be a 50/50 split but I'm not sure what else needs to be clearly agreed upon to make the transition easier. Any advice greatly appreciated!