Growing up I never had an interest in dating girls, but I failed to conclude that meant I was gay. Part of my denial mechanism was that I acted too masculine to be gay, at a time when the sissy stereotype was very prevalent and formed my own view of gay men. They were sissies, I was not, therefore I was not one of them.
Already an Army officer, I had returned to college for degree work and finally made a deliberate decision to date for the very first time in my life, at 26. All my fellow officers were either married or involved with women, plus my parents were becoming desperate about my lack of interest in females. OK, so I'll play along and try this thing, I thought to myself, and college was a good place to meet women, whereas the Army was still a mostly male environment.
I forced myself to do it, but I wasn't very good, and I failed to experience all the "fireworks" and excitement everyone talked about. Sex felt OK, but otherwise was a messy, smelly, yucky ordeal for me.
It took years more before I finally accepted my own orientation. The key was encountering gay men in the civilian world who were masculine, and who assured me that many masculine men are gay, in every walk of like, including the military. Once that prop to my denial mechanism was removed, I came out almost instantaneously. And I've never once regretted it.