I would like to poke a girl that is my friend in school I want to know how I can tell if she will like it and when I should poke her?

You shouldn't touch her if you aren't interested in her. If you're not trying to flirt with her, why do you have to "poke" her at all. For one, 'poking' is very annoying and it's a mean thing to do to anyone. It might be "fun" for you, but you might make her mad. Imagine the ugliest, most unpopular girl in the school, coming up to you while you're talking to the 'fellas' and poking on you? Would you consider that "fun"?

There was a "boy" (and that's what you are if you can't control your hands) who would poke me when we were in high school and I found out that he had feelings for me but didn't know how to express them. I had slapped him before I found this out. Grow up. Find something constructive to to do with your hands. Write her a letter; make her a gift in your shop class, or just tell that you like her, because you do.

I think he means in the sexual way rather than in a way of annoyance. If this is so, you should wait until she is ready and wants to do it. And trust me, you will be able to tell if she likes it or not ;)