I wouldnt try to pick a guy right now. I would take it slow and see which guy actually likes you. It sounds like the first guy might like you. Guys like to hang out with girls that they like. It might be as a friend, but it also might be more. I would test the waters. Maybe try to hold his hand or when you are leaving, give him a kiss on the check. See how he reacts.
I would also try to test the water with Zach. See if he would like to hang out sometime outside of school or eat lunch with you.
Technically, this is not cheating or anything because you are not dating anyone. You are just exploring your opitions.
Good luck.
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Thanks everyone for the points. I love you all.