When does ovulation usually begin?

Day 12-15. A woman's fertilite period begins about the 10th day after the start of the menstrual cycle. Ovulation, release of the egg, usually happens about day 14-15 of the cycle.
Varies. Ovulation usually starts about 1 year after breast development and pubic hair development. You can ovulate and get pregnant before your 1st period. I delivered a baby for a 10 year old who had never had a period.