My best friend's mom and stepdad are 15 years apart, her mom being the older one in the relationship, they are incredibly happy together and have a very healthy marriage and relationship. What matters in a relationship is how two people compliment each other, and how willing they are to work together. I don't see a problem with age diffrences as long as both parties in the relationship are legal adults, it really doesn't have a huge implication on the relationship unless you allow it to. I was involved with a man 11 years older than me for about a year and a half, the issues in that relationship was never because of age, but because we had conflicting beliefs, morals, and personalities. What matters is that both of you are happy and healthy in this relationship. I wish you the best.