Comparing to this Gallup poll of adult Gen Zers (18-25 year olds):
High schoolers: 26% LGBTQ; 12% bisexual, 11% questioning/other, 3% gay/lesbian
Gen Z adults: 21% LGBTQ; 15% bisexual, 3% questioning/other, 4.5% gay/lesbian
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They also found that, among all high schoolers that have had a sexual experience, 1 in 5 have had a same-sex experience (20%; 14% with both genders, 6% only with the same gender). Assuming that number will probably go up for them as they have more experiences.
And I feel like that's pretty interesting to note, because there's an annoying stereotype going around that most bi people, especially bi women, will only fall into opposite-sex experiences because they're a 1 or 2 the Kinsey scale. Obviously those people are valid too, but I don't think they represent the majority of bi people, and there's often some invalidation coming when people say that. I saw this study posted on Reddit, and people were like "it's probably just 99% straight kids looking for attention and trying to feel unique." That just isn't true.
Some anecdotal talk: I go to a progressive-ish college, and from my uni experience so far, I'd say like 1/4 of the people I became friends with at random (mostly guys) have ending up telling me they're LGBT in some form or another. And yeah, most of those people are bi.
Most bi people I know don't seem to have a preference at all, actually, a good chunk of them (including me) seem to have a preference for the same gender. I think I know one bi guy that says he only likes very feminine guys and enbies, so he's only been with girls so far. But other than that, all the bi people I know have either been with both main genders or only the same-gender! I had a talk with my straight friends actually, a lot of them said they have maybe a 5% same-sex attraction, but wouldn't identify as anything but straight because they can't see themselves with the same gender. I mean they could if they wanted to, that's probably an even much larger chunk of the population, but I'm assuming most people like that will keep identifying as straight.
28 and even just 10 years ago I was terrified of classmates knowing that I was trans. I remember one kid who was openly gay and decently accepted but anti trans jokes were still the norm if the topic came up.
I think a big part of this is the area, rural south is still rough for LGBT youth even now after all. But it's gotten a lot better extremely fast at least.
Hell even just a bit before that when I was in mid teens one of tge psychiatrists was trying to convince my parents it was just a fetish. I think I got unlucky cause he was an old old dude but still, I don't see that happening as often anymore unless you seek out a conservative on purpose.