Getting the timing right to get pregnant

Okay, so me & my boyfriend are trying to get pregnant, we are both 18 & I've been taking prenatal pills too, but this is our first time trying im in my fertile window now & I ouvlate on the 16th I think. we've been having sex for the past 3 days & I just wanna know if any of you got pregnant on the first time trying & Does having sex at night change the possibly of getting pregnant or does it not matter? We just really want a baby