Here's what my friend that's not me

has to say about this:
lol @ some of the answers on this thread -- you're going to give the poor kid a complex. You shouldn't be doing shrooms, especially if you're young, but since you will anyway, it's a pretty fun time. I don't partake anymore, but used to have a lot of fun in college -- I consider shrooms "acid lite"; as someone mentioned, I consider it an "outdoor" drug (whereas I consider acid and indoor drug).
It's pretty much like being intensely high (off good weed) for a long time -- you will laugh, and laugh, and laugh; you may trail or get visuals, but nothing as harsh as tripping on acid. Tripping is a mindset, if you're all nervous about having a bad trip, it'll follow. Just go into it in a good, positive mood and you'll have a good time -- it's all a head game.
If you don't eat too much, it's fun to be in crowds, clubs, etc... Last time I shroomed (which was on a New Year's Eve several years past), me and my buddy ate a gram and a half each (or maybe 2) in a pub bathroom and hung out and partied all night (although we did end the trip in a deserted warehouse after it got a little intense)... If you eat too much, you won't be able to handle yourself in that type of environment and will need to go someplace more people/stimulus free.
Depending on the strength, about a gram is a good place to start for dosage, error on the side of caution though, you can always eat more later. Go for the caps, not the stems...
Have fun

But be safe -- and if you're not sure, don't do it.