I’ve never had a pregnancy scare in my life and got pregnant on the first cycle we tried. We were 29 & 30 when we conceived.
Food and exercise don’t really affect fertility (unless you’re under/overweight OR you work out so much/eat so little you have amenorrhea). But generally barring any health complications on either parents side it should take < 6mo if you’re under 35 and < 1yr for older couples.
I also want to add if you do end up taking longer than normal, don’t automatically assume the issue is on the woman’s side…it’s equally as likely the issue is your partners (low sperm count, motility, etc) and most clinics will want to get you both tested.