you should definitely trip with a few choice friends, shrooming in a crowd is bad idea. Take 1/16th of an ounce for your first trip; that's what I took and it was very mellow. an 8th (3.5 grams) would give you a very intense trip, but it can make you freak out. consider your body weight when choosing a dosage. Also know that the caps will give more hallucinations and the stems more of a body high.
A few times I've tripped I got very introverted. The last time I took a whole 8th I sat completely motionless for four hours straight, aware of what was happening around me, but my inner monologue was going full blast. My friends thought I was comatose and threw a ball at me, which I caught and scared the shit out of all of them
the moral here is if the shrooms are good, you don't need a lot of them. Too much of a good thing can definitely give you a bad trip. smoking weed is fun on shrooms, and in my experience helped clear my head wheni was coming down.
Another tip: Shrooms taste like SHIT. You do NOT want to taste them. Have a good thick chaser like a milkshake or smoothie handy, plug your nose with one hand, and use the other to shovel shrooms and pour the chaser in your mouth. The more you chew them the quicker they'll kick in. Keep your nose completely plugged untill you've gotten all the little bits out of your teeth. The cleaner your mouth is before you unplug your nose, the less you'll taste the ass flavor. Somy of my friends say it's the pussy way to eat them, but they can go ahead and enjoy eating dehydrated shit. You'll probably feel a little nauseated for a while after eating them, but you won't throw up (maybe some dry heaves at the worst)
Just remember, it's all just a trip. It may make you think about things in a different way; but the world hasn't changed, just your perspective. If you're worried about freaking out (which can happen if you let it get to you), go to a local GNC or equivalent beforehand and pick up some niacin (vitamin b3). If you start to freak out and want to bail, 250-500mg of niacin will have you feeling more normal within 20 minutes or so.
I'm not one to condone illegal drug use, but it's your decision to make, and I'd feel much better about it if you had the benefit of other's experiences and knowledge before you take your first step into a bigger world. Go forth and have fun!
edit// and yeah... what's the kleenex for??
2nd edit// Also, going for a walk with your friends can be pretty fun, just remember where you're going! I've gotten lost a couple times