hc obviously but i think albert’s realization of his own sexuality was around his late teens. after a long period of umbrella-forced isolation and having no friends, being shoved into his first communal space with people his age or older was almost a shell shock tbh. since it was the 70s, and it was extremely common and favorable to be anti-homosexual, there was an understandable fear of coming out, being implied of being, or even being seen as queer in a public space. especially in a midwestern city like raccoon/its surrounding towns and cities. in the 70s, especially in the later years, there were various anti-gay political movements going on throughout 1977-1979. especially for a child raised catholic (im assuming based on location and including that i hc him as german), homosexuality was a sin. the dsm included homosexuality as an illness, as well as it being an actual crime (sodomy). it’s not like the anti-gay sentiment was avoidable for him in ANY way
wisconsin was the first to make it a law that workplaces couldn't discriminate based on sexual orientation in 1982. until then, obviously it was heavily frowned upon (including a crime etc from what i said above). from what i understand about umbrella as a company, it would have been possible not only for albert to have been fired had anyone found out, but if someone knew this about him they could have used it against him. all of that adding onto the fact that spencer obviously had a big focus on albert in general -- things could have gone wrong in a million different ways re: blackmail, accidental outing, being caught etc.
(again, hc) i think albert's first .. anything was with william in the beginning years of being leads at arklay. i.e most likely a small kiss or something. william probably would've been the only person who knew or had suspicions. we're shown repeatedly that william is one of the only, if not the ONLY person wesker trusts. they'd met as teenagers, were probably roomed together, engaged with eachother in public communal spaces, worked extremely closely together, and were promoted together to arklay in 1978.
albert joined the army in 1990/1991, and i think that was the first time since the training school that he'd been in such close contact with other men, especially in a communal space. barracks, shared showers, etc. had it been his choice, i think he would've rather removed himself from all of that completely and just changed his clothes in a bathroom stall or something. i think his first actual real sexual experience with a man was while he was in the military, considering he was there from 1990/91-1995/96.
ultimately, i think albert was pretty good if not completely adept at hiding his attraction to men for a very very long time, until at least 1996/97 for obvious reasons.
there's many things albert carries shame for and i think his sexuality is definitely one of them, if not THE one. living through both the 70s and 80s provides a lot of fear and dread when it comes to his sexuality in general and i think it's something he struggles with consistently even as it becomes "more accepted" etc