Trying to get pregnant

Hello the last week I finish my cycle pills and I decided to stopped them after 2 years because I want to have a baby, I’m almost 39 years old I have a 11 years old boy this time I wish I can have a baby girl! I’m so excited that I will start taking folic acid and vitamins before. I read some articles about how to get pregnant with a girl and it’s trying days before ovulation so my chart says my window start on feb 13 and the ovulation day is on feb 16 so should I try 3 days before 11 or 16? This is kind of confusing. Has anybody experienced this?