Just because they're you're room-mate doesn't mean you gotta have sex.
WHAT??!!! Didn't stop Baldadonis from pawning at me the whole time.
On a serious note, just save your money. You are young and may only have a part time job, so save save save. You have a registration fee to pay for up front. Beyond that it will be a 3-5 day event depending on what you decide to make it. That's that many days of lodging, eating each day, and travel expenses. That's pretty much it for the planning ahead.
Beyond that, follow CrystalLight's link to the NEST section of the forum. You'll see a lot of people talk about the adventure and questions people ask about it. You've already started going to Dave's munches, and trust me, the one you went to was a small turnout because of the holiday. His munches will bring in as many as 30+ people sometimes so you will start getting to know people quickly. Beyond that, get to know people on the forum, and participate in threads. Going in knowing people does make it a little more calming, but quite a few this year went in knowing no one and just made their way around meeting people.
As for the rooming situation, I'm with Dave, don't feel you have to limit yourself. People want to go, and for most sharing a room with one or more makes it a possibility. You'll see people put up thread closer to the event looking for roomates, if you don't end up working something out with someone you get to know before then. As for female only, that really means nothing. Female doesn't guarantee any kind of play at all, and on top of it, at a gathering, the room is literally a place to crash your head. So many people stay up all night, and go nap for an hour or two, than wake back up and do it all over again. Between me and 2 of my 5 roommates in two adjoined suites we slept an average of 1-2 hrs every night for 4 days. So whoever is also in the suite really matters not.
Anyway, there in an entire NEST section of the forum. Cruise through, read, learn, and ask any questions you have. There are literally hundreds of peoples to answer your questions. Going will be the best thing you ever did.