I doesn't matter. True love is blind - so if you're really in love with someone age should not be a problem. I mean, I have a friend who is 18 and his girlfriend is 29. When I first found out about it I was like: "Eeeh, it may be pushing the limit... just a bit," but now I'm fine with it. If it works for them and they're happy then I cannot see why I should have a problem with it.