With my now 27 month old, I didn't get my period back until I completely stopped nursing her, at 11 months old. At that point, she was only nursing once in morning and once at night! And just nursing THAT little kept my yucky period at bay. Oh, the joy LOL.
With this one, I had to supplement because I wasn't producing enough, and all the pumping in the world and nursing didn't bring it back up. It's down to ONE nursing session first thing every morning, and she eats formula all day. Still, I have no period. Baby's nearly 5 months old, has been nursing ONCE a day for about a month now, and nursing ONCE a day has so far kept me from a period, yey, me! LOL Hope your luck is as good as mine, eh? LOL