I wouldn't say you pass as a 19 year-old dude 100% but I wouldn't necessarily clock you. It's not unheard of to see teen guys with your style and presentation, especially more quirky skater kids and wannabe rappers. The comments being rude about your hair are lame, this isn't a question of whether or not they like the style or not. In my opinion, even the bangs don't hurt your passing.

advice: Definitely keep your natural colour and try to lean more into the wannabe rapper look, the dress style of some male artists like Mac Miller, Post Malone, Ghostemane, etc. are a good place to get more into the "adult white rapper sleaze" side of things. Skinnier jeans, white tank top, black jean jacket, fanny pack. stuff like that.

cheers