Hi Circle M, I'm pretty new to cattle and am probably the last person on this forum who should answer you, but here I am.

I'm farther west than most of the members so I'm apt to be on later.
You should wait about 60 days after your cow calves before breeding her again. If you keep more than one cow, you'll know when one's in heat because the others will begin mounting her and she'll stand still for them. If she isn't in heat, she won't stand still when mounted but will move away.
I hope this helps.