It can be normal, although it depends on what triggers those thoughts.
It happened to me a lot when I was 17. I started having homicidal thoughts simply because I had a huge hatred towards my classmates who always excluded me in class and never wanted to socialize with me. I remember that another thing that made me have those thoughts was watching quite a few documentaries about serial killers or school shooters to feel identified.
The good thing is that the pandemic kept me away from all that sc*m. Although unfortunately, it also worsened my mental health.
Currently, I don't think about those things anymore, because basically I'm no longer in school. But yes, school makes me think about those things.
For me, having homicidal thoughts is equivalent to thinking about CTB, because here the hatred is not towards oneself but towards people.
I had this belief that I didn't deserve to CTB because I never did anything wrong; instead, I thought that they should leave this world because they were the ones responsible for making me feel bad.