Moving in together

My bf and I have only been dating 10 mo. We have grown and learned that we truly love eachother, and do want to be together forever. He is 28 and I am 22 (not that age really matters) but he has been on his own for quite sometime. He said we really wants to buy a house and move in together. However, his parents are extremely conservative/traditional and would not approve of us moving in together without being engaged first. I told him that I did not want to get engaged yet because my twin sister is getting married in October and I do not want to take away from her celebratory year (if that makes sense). I don't know what to do about this situation. Besides just loving the holy crap out of each other, financially it would be easier. We are also in a LDR currently and really want to see how we work together even before an engagement. Make sense? I need some advice.