Only problem I can see is that with such a gap you will both be at different stages in life - generally, people of different ages want different things. This becomes less and less of an issue as you grow older - ie, somebody of 42 is often very similar to somebody of 49 but somebody of 20 can be quite different to somebody of 27.
You know, you might want to go out on the town, she might want to flick through a catalouge of curtain samples..
Whilst age is sometimes not a problem, I do think it is somewhat shortsighted and idealistic to state point blank that it simply 'doesn't matter'. Although its entirely possible it can work, it is more likely to have issues than a very small age gap. As an example (And NOT in a relationship sense but merely to illustrate my point of how people of different ages can be different) can you remember how different you were at 14 to how you were at 7?
Blissfully happy or not, the age difference alone gives you complete manipulative control over the relationship.
gutted now 
