Wow, I can't believe Miss P is nearly 1!
My AF came back when my DS turned 15 months (in June last year). It was a regular 29 or 30 day cycle until last month, when I had a 23 day cycle. Now I am on day 31 and still no sign of AF (and I'm not pregnant, lol). I remember AF being a bit heywire with my other DS too. It returned when he was 13 months for 3 cycles, then vanished entirely for 3 months.
I am still bf, so I am blaming that! It is a little annoying though, not knowing when 'she' will turn up!