You may not want to hear this, but I can speak from literally years of experience in swinging and p4p.
There are many things wrong with this scenario as you've described it.
Newbies at their first swing party are notoriously awkward and unsure. So here you would be, with a lady you've just met... And she is there not because she's interested in you, or in swinging, but because she needs a paycheck.
I'm all for trying new things. I love the great times I've had in a swing environment. But it took me years before I agreed to take a paying client into a swing party.
There are many social protocols and pitfalls when it comes to navigating a group event. I would hate to see you spend good money (although $400 is hardly fair for 4-6 hours of a lady's company) only to find that you, she, or both of you feel that this event may not be for you.
If you have a civvie friend you could invite, I'd recommend that.
Just some thoughts from an old hand at group fun.
-- Modified on 2/3/2015 5:33:16 PM