There's room for a different choice.
Once upon a time, there was a very clear, natural progression of how a couple moved through a dating relationship, from one phase to another with a higher level of commitment. They dated, became engaged, got married, and, finally, moved in together. Any other choice, years ago, would have been frowned upon and maybe even whispered about.
Of course, that has all changed, and now we see and generally accept any choice people make in the order in which and the way in which they commit to each other —as long as both partners are on board. Whether they want to live together first, have a family first, or, possibly even, commit their lives to each other and never share a home, it is all happening out there.