Age is immaterial but maturity is. It is usually seen that mens mature later then ladies, this is nature's principle. girls attain puberty in a tender age whereas guys take a longer time.
I don't think so that it would be problem b'coz a year difference doesn't matter.
And as such there's no marriage successful formula. As you are taking one of the "most important decision of your life" I would advice to consult your elder's and boy's elder. Elders advices are invaluable b'coz the situation u and i go through, they have already experienced. So please...
And one more think, don't hurry.. Remember, "its a very important decision of your life".