At the end of the day you are the one that will have to live with your choice, I got married at 23, and that was the right decision for me, my husband had a previous marriage and they were both 24 (he is 7 years my senior) when they got married and it fell apart very quickly. The reality is that almost half of all marriages end in divorce, and there is no guarantee that your relationship is forever, and marriage is more then just a beautiful wedding where you get to be the center of attention for a day. It takes a lot of work and compromise to make a marriage work, and even the happiest couples will hit rough patches. If you think that he is the one and you are ready for such a big commitment, then it isn't for anyone else to say when you are ready.

I am pretty much in the exact same situation as you. My boyfriend is still in school, though, so we won't be able to afford to get our own place or start planning a wedding or anything for another year (at least) but at the moment, I am living with his parents and siblings. His mom wasn't sure about it at first, and her friends all told her she was nuts, but she says that she loves having me here, so I guess she adjusted, but my mom still doesn't think we should be living together. She keeps saying she thinks it's too soon, and then when I mentioned my boyfriend's plans for my engagement ring, she seemed surprised and not all that thrilled at the idea of us getting that serious. But no one in either of our families has voiced any kind of blatant disapproval. I'm lucky to have parents that let me make my own choices (even when they don't agree) and I know that they do love my boyfriend, so I have faith that it will all work out in the end.

So basically (sorry for the long backstory) I say go for it. You know how you and your boyfriend feel about each other, and when love is that strong, eventually other people can see it too.