Chris, the way to get ready to play with others is, curiously enough, to go out and play with others. That moves you forward faster than any other approach. Welcome to the club!
You don't need to know too much about amps, except what you like. If it sounds good to you, then it's good! If it doesn't, well, then maybe it isn't for you. And if you haven't already, check out the Rumble Club once you get your Rumble 200 (great choice!). @G-Dog will be happy to give you a number there too!
I'll ditto what these fine folk said. I assure you that when I first started playing guitar with others, I was verrrry early in my journey - but it did more for me than anything else. Ideally, find a group of people you gel wit that are at least a little better than you. Worst case, find people at your level or a little behind, so long as they're working on getting better, and play as much as you (reasonably?) can. Play along with recordings, too!
