Lab may be pregnant

Question
How old does a Lab have to be in order for her to get pregnant? I am not awaire of her going into heat yet but she is eight months old. If she is,is that a bad thing?
We had wanted to bread her with our yellow lab, she is chocolate, but didn't plan on this soon! I just want her to be OK! Thank's for the help.   Donna

Answer
A female large dogs cycle normaly starts later then that of a small female...my labs first cycle was at ten months then ten months later and then I had her spayed. You will notice a bloody discharge and some odor when her cycle starts then you keep the dogs seperated for 2- 2 1/2 weeks or she will get pregnant and she is too young to sestain a pregnancy and would be hard on her developing joints since she wont be fully grown until 18-24 months.