And this was okayed by the school? Even with the anonymity, that seems like it would be shot down right away.
Well, generally it is different your first time than afterwards. I didn't get any kind of mellow feeling like I do now, it was just giggles. You may not even feel any different. You could try holding the smoke in longer if nothing seems to be happening.
If it does, though, be careful about it becoming a habit. You're still in high school, right? So you're probably in the process of figuring out your life goals and how to manage your time properly? Pot has been known to throw a wrench in that part of people's lives, in my personal experience. You'll probably be alright, but as a rule if you have homework you should take care of that first because there's a strong likelihood you won't feel like doing it afterwards. Some people can function normally with a mild high, but it can take a while to find that balance, so I guess just use caution and common sense.
Sorry if it seems I am acting like a parent, my brother's just a useless pothead and I would hate for someone else to end up in his position because of me.
Edit: yeah, munchies might be a good idea. And water. Pepsi might taste better, but I've actually gotten minor dehydration from some of my lazy afternoons before, although I seem to get dehydrated easier than most people so maybe that's just me. Try to get a glass in somewhere just to be safe.