Trying with 0 luck

I am 19, and my SO is 20. Me and him have been trying for almost 2 years now and we have had 0 luck. We have never had a vfl or a scare, or anything and I’m getting discouraged. I was having extreme cramping every cycle and they thought I may have had endometriosis but had a laparoscopy and everything was good. She said she hasn’t seen a Better pelvis. We use preseed on my peek day and try to have sex every other day of my fertile window. Has anyone ever tried and tried with absolutely no sign of a baby any time soon but then still get pregnant? How long did it take?