First of all, I'm a straight female in a long-term relationship, 32 years old, with two young children.
I've had anxiety as long as I can remember (I don't have a single memory in which it doesn't feature somewhere), but things really kicked off when I was 17 - I got pregnant by mistake and then had an extremely violent and unpleasant miscarriage at around 12 weeks that landed me in hospital. I recovered, but was left feeling extremely ashamed and devastated that it had happened. After that, my anxiety became unbearable.
I'm 32 too and have also experienced something like this. I've never admitted it to anyone so this is new for me, but this story really resonated, so here goes ...
Your story of the boys in your grade was so familiar.
I know of the movie. I haven't seen it but did see the first one so I can imagine the sort of theme. I remember seeing the original 'It' movie when I was very young and being so scared that I was physically sick. It haunted me for many years.