That's not completely true. The vast majority of women do not ovulate immediately before or on their period. If they did, it wouldn't allow the fertilized egg time to implant into the uterine lining or it would be flushed out with the rest of the tissue.
@sammy
Most women ovulate around 14 days before their next cycle is due, but this can vary from 10-15 days and is called your luteal phase. Sperm can survive for roughly 5 days in a female but under perfect conditions can last as long as 7 days. For best results, sex every other day yields the best results. This allows time for the sperm to build up again. I also advise patience. It takes on average 1-2 years to naturally conceive, and less than 50% will become pregnant in the first 6 months. Don't have high expectations, and don't put on pressure.
usually before you start your period and or while your on your period your mostly like to get pregnant
Your body is most likely getting ready to ovulate for the first time since being off birth control.
The more it looks like egg whites and stretchy it is...the more fertile you are. Keep track of all these things and you will find a trend in your cycles.