Birth control after birth

How soon after giving birth can you start birth control? I will be exclusively breast feeding (I hope). I am a first time mom and I do not want to get pregnant for a few more years and since I got pregnant using condoms and birth control, I account that to my boyfriends freakish sperm lol. I would just like to be protected. Maybe have another baby in the next 3-5 years. I want to enjoy my little boy for now. I'm currently 27 weeks.