Dear Brendan, basically you’re the age my eldest son is and she’s the age I am…both in a few months, anyway. Do your reservations come with the fear that you’re thinking of marrying a woman old enough to be Mom? You obviously are fond and get on well, but my sons adore me to bits too. They have never tired of saying at odd moments, embracingly, with love in their eyes"I love you, Mum". I love my sons to bits too. I’m considered as looking years younger than my age and people seem drawn to me, but give me five to ten more years and I’ll be a white haired old lady!
Friend, if you have reservations, as you say, they are more likely to grow than to recede as time passes.
As you have reservations, it will be less painful to admit them now rather than later, and a lot harder to break out of, in fact could ruin your lives, yours for many years longer. Two of my sons had reservations, both broke up, after a lot of mutual pain.
God grant you strength to do whatever you must.