You have to pay for a doctors answer. But, I do I agree with the guy above, bigger is not necessarily better. I have actually told a guy "no way" because his penis size scared me away, it was too big! I wouldn't worry about it one bit, especially if you're getting married. I'm sure you're just fine.
I don't think you need to be worried about the size of your penis. Some women don't really care about size so it shouldn't be a problem. However, if you are having problem with erection, then you better talk to your doctor.