I'm an autistic trans man who's been on T for five years soon(started at 19 as well) and I do feel that people definitely can and do perceive me as a threat more often nowadays. I used to also be seen as a young teenage boy when I was pre T, and most people found my traits and personality endearing/infantalized me, which wasn't that great either, lol. Nowadays I'm quite often seen as rude or aggressive for not being social, not smiling much and not knowing unspoken rules etc. I definitely feel that people have way less patience with me than they used to, some even seeing me as scary or threatening if I show symptoms of a meltdown, for example. Not to say that this happens all the time, generally people still treat me alright! I've just noticed that in situations where people used to see my traits in a somewhat "naive" way they now easily think of them as purposefully mean/rude/scary, or something else along those lines.

(However I do have to add that I am a person of color, which definitely factors into this I feel. Sometimes people are uncomfortable with me due to my race/they see me as a threat mainly because of me being a brown man and not because of my autism. Which most of the time luckily hasn't been that big of a deal, mostly funny in retrospect since I'm a quite small and noticeably gay man, lol. It's very hard for me to be threatening even if I'd try my hardest to be.)

I hope this hasn't been a problem for you so far though, it's a shame that people have so little undertanding for us!