If she hasn't had a litter before, she may have trouble getting pregnant. Which is why folks talk about a 'proven' doe. Usually, when there is a doe in the breeding herd, I try to get her bred before she's a year and a half but before two by preference. But, every rabbit is different, just breed her and see if it takes.
I've had a six year old doe have a first time litter, although that wasn't a planned litter. I'd put a pair of young does in with the doe herd and then went on a long vacation. Came back to find out the sex change fairy had made a visit. Out of ten does the young buck was with, the only one who had a litter was the six year old doe. Maybe the rest of them didn't like the buck, or maybe he only liked the one doe.