Inverted nipples are pretty easy to identify. Check yourself by gently pinching the base of your nipple. Does this make your nipple retract into your breast? If so, it's inverted. If it pushes it out, it's not inverted. And if your nipple barely sticks out or sort of stays flat, you have a flat nipple.
You may have heard that flat or inverted nipples can make it more difficult to breastfeed, but don't stress. Babies don't "nipplefeed." They breastfeed. There's a good chance baby will be able to latch on and draw your nipple out on his own. To help him out, give him optimal conditions: Try to nurse him as soon as possible after delivery, and avoid the artificial nipples of pacifiers and bottles. Ask for help from a nurse or lactation consultant. Ask for her advice and have her make sure baby has a deep latch.
If baby does wind up having trouble, definitely enlist a lactation consultant to give you hands-on advice, customized to your specific needs. She may suggest pushing back your breast with your fingers to make your nipple protrude, using a breast pump to bring your nipple out, or wearing breast shells before feedings for a couple of weeks, until you and baby get the knack of it.