I still feel guilt over violent thoughts i had as a teenager

Hi,everyone. To clarify, i am now 20 and these violent fantasies took place when i was 14/15. At the time my home life was loving but very chaotic and unstable due to my mom's bipolar and my dads alcoholism. At school i was incredibly shy and struggled to fit in. I was ostracized and often ignored. I know that how quiet i was played a part in this social isolation but i felt overwhelmed during this point in my life and the occassional bullying from two classmates at the time crushed me.

Around this time i became fascinated in school shootings and true crime. I had violent fantasies about shooting up my own school and hurting these classmates who had humiliated and hurt me. I was guilt stricken by these thoughts but at times when i got angry i would have them to coop and feel like i had some power and control. I was disgusted with myself, and never actually planned on shooting up my high school or anything. To me it was to not feel so small as well as just a morbid curiosity as to what would happen. These thoughts stopped at the end of my freshman year.

As i mentioned above, i am now 20. So this is well behind me. Im in school, i work, i have a fairly good relationship with my family and am engaged. I have a pretty good life id say. But i still lay awake at night on occassion and feel horrible that i had such dark thoughts and fantasies. Were these thoughts normal? Is my residual guilt normal?