I am late twenties and I'm telling you it happens to me everytime I go to a public place in the UK (usually Birmingham for work). I would say I'm attractive but I don't stop traffic, usually dressed fairly normally and smart, nothing attention-grabbing e.g. heeled boots, smart jeans, blazer when I'm out and about, or even more casual stuff.
It can be anything from being 'bossed about' by men e.g. being told off, being told what to do (e.g. don't stand there, don't drink that, you shouldn't be on your phone so much etc?? I firmly put them back in their place), to sexual/creepy comments, to people just trying to chat me up but very forcefully and in an intimidating way, to being intimidating with body language (e.g. back me into space and start talking, or block exit point with body or arm), locking doors of taxis and refusing to let me out til I've said or done xyz, all the way to physical contact, from just creepy all the way to sexual harrasment.
It happens everywhere, in the centre of town, on a quiet street, in a car park, in shops, on trains or in stations, on planes. I wish I was lying about this or making it up for attention/stealth brag, whatever you want to say. I'm a confident woman that just goes about my business, but perhaps I do just have a vulnerable look about me? I hate that, and I hate that I have to almost practice what I'm going to say or do when I feel these situations arising.
There is a horrible horrible misogynist culture in the UK and when I react or shout back, more often than not I've been given dirty looks or told off by passers by for making a scene rather than supported!
Luckily I live in a city in mainland Europe and it NEVER happens here (in the 5 years I've lived here).