I never had a threesome... or did I?

Things were clear when me and my girlfriend went to a birthday party. She a luscious metalhead who had a lot of experience in sex and me who lost the virginity pretty late in our relationship. I mean she wasn't that outgoing maybe just a normal teenage girl experiencing sexuality (but in hot metal clothing; (is't getting obvious here that i have a little fetish going on here)). But what I didn't know was the confession she made later one - and of which, up to this day, we never spoke again. The birthday party started like every normal party. Random chatting, drinking, chatting with different people, stealing a kiss from my girlfriend while walking past her and later on: Party games. The atmosphere was quite liberate especially about sex and especially when the night went on and people got tipsy. We played the game "I never have". A person tells a story beginning with "I never had" but the story which follows after is a story the person actually experienced so it is a lie and all other person for whom the sentence is true have to drink. After normal funny stories my girlfriend shocked me when she said. "I never had a threesome." I was instantly hot for her. And then one confession followed the other. My girlfriend joined in: "I never had sex in during a concert". "I never had sex in school". Oh My. The looks of the other girls and boys listening to this stories even made it worse. When we walked back home and I asked her about the stories. She just smiled.