How many days before your period is ovulation?

I've seen several women on Glow say that, although ovulation isn't always 14 days after your period, it is always 14 days before it... Is this true?? According to glow I ovulate really late in my cycle (last month I O'd on CD 27),  and it was only about 8-9 days after that I started my period... I know I shouldn't really believe everything I read on here but it got me wondering and I couldn't really find a solid answer... I really hate when people give out information on here that they don't know is 100% true.