First Time Lesbian

Right, I was 16. I was sat in my bedroom on my bed with my brother's 18 year old female friend. I'd recently had a fall out with all my friends and she had agreed to keep me company and try to cheer me up. I knew she was a lesbian and it intruiged me.
"So," I said, "if you don't mind me asking, how did you know you were... a lesbian?"
"Haha, don't act so timid." she giggled, I couldn't help but notice her breasts wobbling when she did so. She was wearing a tight red dress, very short and very revealing with no tights. I listened to her, "I don't mind people asking, it's a reasonable question. I guess it was in high school when all the girls were getting changed for gym. I couldn't help but stare when they stood there in their underwear, and there was this one girl I couldn't ignore. She had big tits and always wore thongs to show of her perfect ass. So I started to wonder whether I liked women, so I decided to watch some porn to see if I did, and God did I enjoy it. The way their tits bounced I just wanted to reach out and squeeze them." She looked eroused.
"Fair enough. To be honest, I think I like girls, but I'm not sure. How can I tell?"
She smiled and kissed me, her tongue in my mouth. It didn't last long, but the effect of it did.
"Well, did you enjoy that?" she asked, smiling seductively. I nodded. I could feel myself getting wet, and then wondered if she was wet, then wondered what she tasted like. It was like somebody had flicked a switch, suddenly she was standing up and pulling her dress and shoes off.
"Um, what are you doing?" I asked nervously.
"It's another test, to see if you're into girls. Stand up."
I did as she said.
"Take off your clothes." she ordered, while taking her thong off.
"All of them?"
"All of them."
I was so nervous I did what she told me, until I was stood there naked. She stared at me, wearing nothing but her bra, "Fuck, you're hot." she breathed, "Okay, give me your hand." She took my hand and put it between her legs. She was wet, "Like it?" she asked. I nodded. She gave me my hand back and reached around to unclip her bra. She took it off and her tits bounced, she was at least a D cup.
"On the bed." she shouted, giggling. I smiled and led on the bed, she pulled me until I was on the edge of the bed, my feet touching the floor, my body still on the bed. She knelt down and pulled my legs apart, "Tell me if you like this." She dived between my legs and shoved her tongue inside me, her hand rubbing my clit quickly.
"Fuck!" I shouted, "Fuck yes! I like it!" I felt her smile as she started to jab her tongue in and out of me. She pulled back and put in a finger. I moaned and she added another one. She fucked me hard with two fingers, then four. I came hard and screamed. The door swung open, her friend stood in the door way, ready to pick her up, "What the fuck!" she shouted, "Kim, stop taking advantage of innocent girls!"
Screaming, she grabbed her clothes, "Lizzy! Piss off!"
"No, you're going home. Now."