Before you sell your bean bag chair on Craigslist and buy $1000 worth of flimsy particle board furniture from IKEA, truly consider whether you’re ready to take this step together. Once you’ve made the leap, there is no un-leaping. The only time you're moving out after moving in is if you break up.
Also, should you break up: Figuring out who gets the apartment, and divvying up all the shit you bought together for it, is excruciating.
So, by all means, get a little introspective about whether you're ready to take the step at all, and encourage her to do the same.