Does a bitch only accept the male when she is ready and has ovulated or would some bitches still accept a male before they are ready? I ask because I think my girl is early in her cycle yet she has bred to my stud and tied 3 times now.

Being receptive to the male is in no way indicative of ovulation. Some bitches will stand early on and others not until they are just about ready. Some males are really eager and persistent and will be able to breed a bitch that is not quite ready too. The best way to know is to do some sort of progesterone testing. Otherwise you can just keep breeding until she is no longer receptive.