I was sure I'm 100% gay but at around 18 some specific type of women (muscular, big butted) started attracting me so i realized I'm like 10-20% heterosexual.

Which is why i question whether

1) my sexuality changed, or

2) i was always bi and could always be attracted to women, but the hetero percentage is so small that i just didn't see these types of women, and thus didn't realize my bisexuality

And someone also suggested

3) that I was always bi but it was a very long bi cycle, so for years i could only experience attraction to men, but that i always had that hetero part in me which only started manifesting itself later

Can someone please help me understand myself because i have a very severe OCD on sexuality since i also struggled with internalized homophobia before and now i have to cope with internalized heterophobia as well its very painful. Thanks!

(Also whats interesting is that even when i was sure I was 100% gay i never felt any romantic attraction to boys, i only developed a very close emotional friendly ties (or bromance), while i had kind of "something" romantic to girls, though overall I'm very genderblind and i never met a person who i would like to live with forever so i consider myself aromantic and I would also say I'm on the asexual spectrum)