No period- EVER

So I have never had a period naturally, went to doctor when I was 17, because I hadn’t started period and after blood tests, brain scans, and pelvic ultrasounds it all came back ok. My doctor put me on birth control and I have periods on it. When I went to another doctor, she ran similar tests and said that hopefully it was just because my BMI was low and when I got off it would regulate. If not, we could consider ovulation pill. I hate it, because I never got real answers on why I didn’t start period or if the doctors even knew. I am 23 now and wanting to start a family with my husband. This is the first time I have been off the pill for this long. I have no idea what to expect. If anyone has had a similar situation, please share! Freaking out that I won’t start my period naturally and/or still not have any answers.