I feel that uneasiness when approaching a group of teen boys, as I feel them staring me down or something. I don't feel it much or at all if it's one or two, but a group of 4 or 6 is almost menacing sometimes. I do dress younger than I am, and I sense that they are picking up instantly on my weird signals, and it feels like they might try to do something. I also have to be fair, and say that they never have done anything besides looking at me funny. The closest I get to trouble is if a group of teen (or early 20s) thug-like guys are with their girlfriends, and the girlfriends notice me. That's scary, as I know they'd pick a fight over something like that.
The best thing I can do is always walk with confidence and purpose, and if I see them staring me down head-on, I keep right on going and give a polite nod and look like I'm in a hurry but not afraid. Or sometimes I pull out my phone and act like I'm checking a text, or I pause to look at something in a store window as they pass, etc. Any diversion. I also have a bit more confidence in my ability NOT to be a good target for any kind of physical hassling, shoving, etc... I'm a 6-foot tall bodybuilder with arms bigger than most mens' legs, and big veins popping out, LOL... And I look pretty menacing as if I could pull them apart like a rag doll if I needed to. (avatar pic is recent/accurate). But on the other hand, I have no fighting or self-defense skills, so the size must not be allowed to give me a false sense of confidence to get me into trouble.
Charles