This is a question that I get alot, and it's an important one. The real issue is how pregnancy will change the shape of your breasts. Unfortunately there is no good way of knowing this. Some women have major changes in the shape of their breasts after pregnancy, and others have minimal changes. There really doesn't seem to be too much rhyme or reason to this. However, women with smaller breasts tend to have lesser changes (but not always!).
So where does this put you in terms of your timing? Well, if it's going to be at least two years before you have children, I would go ahead with this now. If you were thinking about children in a year or less, I would wait. The implants should not affect breast feeding, and they should pose no problems to your future children's health.
Your wedding day is your big day! If you will feel better having a breast enlargement before, I'd say go for it!
Best of luck!