Awww that's so sweet.
Haha well it wouldn't be the end of the world if you were - we're using that method too and we're finally at the point where we can really say it wouldn't be the end of the world if we fell pregnant, although I'd still rather wait until Summer. If we got pregnant this cycle it would be a December baby, my 30th pregnant, a cruise at 23 weeks pregnant and 2 weddings and a drive up to Scotland while I'm about ready to burst... hmm - not the best timing haha.
It's probably just your periods regulating themselves, although I'd never recommend the withdrawal method to anyone who desperately didn't want to get pregnant if it's done right it seems fairly reliable (we've been doing it for years and never had any issues, so either it is fairly reliable done right or we're going to have a nasty shock when we do start trying and find out we have a problem :/)