Yes, everyone is different and you are probably completely within the normal range. I would check to make sure you're not pregnant again, as that's happened to several of my friends. Did you by chance have either a c-section or a post-pardum D&C for retained placenta? There is a condition called Asherman's syndrome, which is basically scarring of the inside of the uterus caused by uterine trauma or surgeries such as a D&C (especially immediately after a birth.) It is a fairly rare condition, but widely under-diagnosed. If you haven't had any of those, then you can probably rule it out. If you're worried about your cycle not starting by now, talk to your doctor about trying hormones (provera or something like that) to get your period back on track. If you did have a c-sect or D&C after the birth of your daughter and the hormones don't work, I would talk to your doctor about Asherman's. Good luck!