If she's reached sexual maturity and has spent any time around an intact buck, she most likely is. Rabbits are induced ovulators, meaning they ovulate (release eggs) as a response to having sex - this mechanic means they never go into "heat" and don't have a "cycle" like so many other mammals.
At a certain point in the pregnancy, she can be gently palpated to feel for the babies, but this has to be done very carefully and as a non-breeder, I'm not the right person to tell you how to do it safely. Hopefully someone who breeds can give you a more detailed answer than I have to offer.