Teen mom, and breastfeeding

After putting a lot of thought and research into it, I've decided to do breastfeeding once my son is here. One thing I'm nervous about, is the looks and comments I'll get when I'm in public. Sometimes, I can be very rude back. Other times, I'll break down and cry. I want my baby to be as comfortable as possible, because nobody else's opinions matter when it comes to MY child, but to anyone who has been breastfeeding.. What did you do the first time you got a dirty look or comment? How long did it take you to be completely comfortable with breastfeeding in public?