[lisatodd]

not to be mean but you should have studied up on this prior to letting them be together while she is in heat. she is also young...most wait til they are 18 months before they let the female get pregnant.
if she is in heat, you should keep a close eye on her at all times. if you have to leave the home or the room, then you need to separate them. the male can get injured during the tie. the female can get very vicious and try to run during the tie. you have to hold them and make the two comfortable. moving the male so they are end to end.
if you have not been watching them, i quess a tie could have happened but you would know if you were there. also, it is at day 9-15 that the female will flag the male. a vet can tell if she is preg a about 30-45 days. some do not show until a couple of weeks before they are due.
to be honest, i think you should hold off on her getting pregnant and wait till she is a bit older. jmo