Sorry to hear about this terrifying incident. You did the right things. I hope you can ignore the men on here doing victim blaming or calling you a troll, or dismissing your concerns.
it is amazing how men simply don’t get it. Female runners are murdered or raped often enough for every female runner to be concerned with safety. The weirdo at the track was definitely a reason to worry. I would have high tailed it out of there too. The vulnerability is why I cannot run alone in one of my local parks. One woman was murdered and multiple women were assaulted there. You would think a track would be safe but really you can be assaulted anywhere there is opportunity.
And another thing. Some teenagers write well and much better than some of the posters on letsrun who are grown ass adults. It’s called intelligence.