Age gap!

I'm 17 turning 18 on September 26th and I've been going on dates with a man who's 32 yrs old, we both are really into each other, have a lot of things in common and very strong feelings, we've been getting to know each other for 2 years and few months... He wants something serious with me as In making me his gf, moving in together and marriage... We've talked about it but I really don't know what to do, I'm more worried about others opinions. I'm afraid of getting judged or to even have family problems both with his family and mine. Any advice? Or anyone with the same age gap experience, how did that work for you?