A little confused !!!

Melissa • I`m a mother of 3 great boys !!! Looking to have a girl ;)
So when your ovulating it's when your fertile days says 33 percent ??? So since I'm trying to have a girl and you guys might think I'm crazy but they say to BD 3 days before you ovulate you have a better chance at a girl !! So that means I should BD 3 days before I'm at 33 percent ???? TIA