I forget what your ages are exactly, but I don't think the age difference matters that much in this case. It's not like you're a high school senior dating someone about to graduate from college. In that instance, four years is a lot because life experience differs a lot (Not always the case, but generally one is still finding his/her way into adulthood, but also still firmly rooted in adolescence, while the other is considered an adult, expected to take care of him/herself completely, with a job, paying bills, food, rent, etc.).

I also feel that you have been through a lot, and your experiences have helped you to mature, which will also even out age differences. I believe that it's not a problem when both people feel that they can learn from the other but also share things with the other, and that neither feels the need to be responsible for the other a majority of the time. It doesn't matter what others think as long as you are both comfortable.

Also, side note, my fiance's dad is ten years older than his mom.