Birth control/ ovulation help

I’ve been on birth control since I was 15 and I am now 20. I stopped in may/june my partner and I are now ready for a baby and we’ve had no luck. We’ve been having sex during my fertile window. I am worried of infertility but I have always had a regular period my cycle is usually 25-28 days. Both of our families have no history of infertility what should we do? I am a little overweight and just want some tips. How do I use the ovulation test kits what days should I?