Correct him

"I'm sorry but you've made a mistake." You tell him "I'm just a high school kid one his way to a Halloween party dressed as Lara Croft."

"And just how old are you?"

"Eighteen."

"So you're just a eighteen year old boy dressed as Lara Croft. So tell me are you a virgin?"

"I don't have to answer that."

"I'll take that as a yes, I bet you've never even had a girlfriend. Tell me how would you like to make a cool thousand dollars."

"Sure who wouldn't what would I have to do?"

"Give up your virgin ass to me."