How do I know if my Netherland Dwarf is pregnant.?

We let our male and female bunnies in together and the male jumped on top of the female and started mating with her. After about a minute and a half he stopped and started preening her. Will she be pregnant even though he is 5 or 6 months old and she is 2.5 years old? When I go into her cage she starts squeaking and won't let me pick her up. Also we tried putting them in the same cage and she started squeaking at our male rabbit! Is she pregnant?