Moving in before marriage controversy...

I am 21 and by boyfriend is 25. We have been together for a year and a half and I'm sure he is the one. We've discussed money, income, family plans, etc. He owns his own house and we both have jobs. My parents disagree and they keep telling me I need to wait till marriage. My boyfriend already has a ring just hasn't asked yet. My boyfriend has also talked to my parents about wanting to pop the question one day and they were very happy. My mom said my boyfriend said "I won't marry someone who I've never lived with" and that's what concerns me....

Opinions/experiences on moving in before marriage?