Transsexual
In case no one realizes: the title is a song by Frankie Goes to Hollywood.
Jazzy has good advice, shockguy, and the ones she's named (including her) are top of the world.
I was looking back at your previous posts, and I think, maybe, you're putting a wee bit too much pressure on yourself and the situation. It's easy to do when it's something new and exciting.
Not only should you choose from one of Jazzy's list, you should really, really chill and let things take their course.
Don't imagine that it all happens in just your first session. I mean, that's a lot of pressure! Since you've probably not even touched someone else's cock before, I suggest, instead, focusing on the oral aspects for your first time. Go slow and explore. Make sure you tell the girl that it's your first time and that you will need exploration time.
You can always work your way up from there if you feel like it. In fact, I suspect you'll really enjoy yourself a whole lot more if you take penetration off the table.
Actually, penetration isn't done all of the time, which may surprise you a tad. A lot of guys just love the oral, sucking and being sucked, and then orgasm.
The neat thing here is: if you choose one of those girls, let them know you are a first-timer, need the whole hour to do stuff and ask questions, I think you'll be very, very happy!
Remember: No talky about sex stuff on the phone!
Make a date and have fun! There's a ton of guys living in areas that don't have your choices, so relax and just enjoy. 
I had a feeling about you that told me, ah, let's use the kid gloves on 'em.
Seriously, ask me any question you'd like, and I'll try to answer as best I can. I really, really understand the heebie-jeebies of first-time visit.
Feel free to PM me if ya like, yahoooooo!