My soon-to-be fiancÚ and I are a year younger than you and your FH. My mom is the exact. same. way. I basically sat down with her and had a long talk about everything. I explained that I understood what she'd gone through, but that he was different than her previous husbands, and we both knew that. She agreed and told me that she wouldn't be okay with anyone marrying her baby until they had said "I do". So, talk to her and then just give it time.
Thanks for the advice, I was thinking of trying that. Sometimes she's hard to talk to though. If she dis-agrees with what you're saying, she'll totally ignore you and tell you what she thinks and that's that.
But congrats on your engagement! _ And thanks again for the advice.