Do you think it's okay that I want to write down every time a girl talks with this guy I like in my journal as if it were a death note?
Why would you want to write down every time a girl talks to this guy?
I don't want any other girls talking to him.
I understand that you like this guy, but it's not nice to wish for bad things to happen to girls that talk to him. If he likes you back then it won't matter if other girls talk to him, so you have nothing to worry about.
I'm going to go out of my way to make sure no other girls talk to him.
Hoping that something bad happens, or even death, to someone that is talking to your crush isn't okay. Talk to the guy you have feelings for and see if there is potential for more. If not, it's time to step away.