Is it normal to plan on killing somebody

Plan as in devise with the intent to carry out or more like a revenge fantasy thing?

Always have a plan to kill everyone you meet

does it count if the person was myself

Pussy.

Not normal, thou shalt not threaten people with no cake, you dig in with your fingers at any time, getting a grasp of hands finding no cake in your pockets.

Depends on how far you went with it. If you were just thinking "I could grab a knife, no one would know", people have thoughts like that sometimes. If you were standing outside their house with a bottle of lye and Glad bags, then you should probably get that checked out.

It's normal to have thought about it at least once, especially if the person made you angry.

Too many people

I have a plan to do some really grim shit if this one person does something

I do that too with people who are mean to me