I don’t think you ever detailed what was so horrific in that sem.
If you did I apologize. Not knowing this detail but obviously she was uncomfortable with something.
I was sent to a Yeshiva highschool in Israel for 10th-11th grade i hated it, but there was no other option that my parents would consider.
In the final analysis I turned out relatively ok so hard to say
what difference it would make had i left there or not.
I so hated it that I caused physical damage to their alarm system so that on Purim it went off in the middle of the night.
The ROsh Yeshvia was very angry and while they had no proof it was assumed that it was me.
Beyond that I then went OTD for about 14 years. So maybe you made the right choice.