Just out of curiosity, how long did other nursing moms go without getting a period while nursing? What kind of nursing did you practice (that is, did you supplement with formula? do any pumping? night wean?)? How long did you nurse?
I read that if you practice "ecological" breastfeeding (basically pure breastfeeding with no supplements, pacifiers, etc) you can go as long two years with an average of about 14 months without AF. I wouldn't know, because I got pregnant without ever having my period return at 10 months postpartum while nursing pretty much exclusively, although we had introduced solids and used a pacifier occasionally.
Anyway, how long have you been able to put it off?