Fertility after depo when you have got your period

Hi,
I've been on birth control for years, since i was 13 to help with my periods. When i was 15 i had the implant which i later got taken out and then i went onto the depo shot. I came off the shot in October 2010 and the first month i was off i had my period, which i read sometimes takes a lot longer. My question is, does anyone know roughly how long it takes for fertility to come back once youve had the first period? I'm aware that the depo does three thigns to your body: 1) makes the lining of your womb thinner so a fertilised egg cannot attach therefore no periods. 2) makes your falopian tubes produce a discharge type liquid to make it harder for sperm to get to eggs 3) and it stops you producing and releasing eggs. As far as i am aware my body has put the 1st thing back to normal as i am having periods so is there an average time for my full fertility to come back and will i be able to tell?
Thanks in advance for any replies.