Virginity lost: 17
Sex for money: 21
I was raped once after I started escorting. The bastard wasn't a client, just a regular date, and the cops told me there wasn't enough evidence to do anything about it. Grr. Therapy helped, though.
Multiple escorts to one client: Yep, that's called a double (or triple if he hired three other girls). Usually the guys who do that just want to watch. Group sex is a lot of fun, although you need a really big bed.
I provide my own clothes, but they're mostly in the vein of "pretty dress + heels." I'm not a big fan of, say, maid outfits or anything like that.