Im worried that someone will find out!!!?

Last night I went to this metal concert with a different friend and a 22 year old guy that so close to her that he's practically her brother. Lets call the guy Tommy and the girl Sarah. Well I also wound up spending the night at their house. Sarah hates sleeping on the couch so she took a spot on the floor. Tommy always sleeps on the couch. Well last night I slept on the couch too. The couch was in an "L" shape. Both are heads met in the corner on separate pillows that were like 6 inches away from each other. When I was about half asleep Tommy grabbed my arm and held it. I slowly inched my hand towards his and then he let go of my arm and held my hand. Soon we were just staring into each others eyes and smiling. He was tracing his fingers around my lips and then he stuck his finger in my mouth so I acted as if it was hi tongue.. Right after that he stood up to see if Sarah was asleep, she was, he pulled me close to him and started kissing me. I melted. I felt so special and admired and for once in my life I felt beautiful and loved. He then came to the other side of me put my legs on either side of him and leaned in to kiss me again. I stopped him and said "Go to bed Tommy" He was like "I know this is wrong I'm sorry" I told him not to be that I didn't mind. He went and lied back in the spot he had before. And we again just kept looking at each other. He was actually looking at me. Not my *** not my boobs. Me. I wanted him to just kiss me and ask me to be his forever. He kept taking my hair behind my ear to see my face and then he'd rub my cheek with his thumb. I scooted forward and kissed him. He then moved his head to my neck and slowly kissed his way down to my chest. He stopped where my shirt began which allowed him to touch a very very small piece of my boobs. He grabbed my hand and placed it on his hard penis. My hand was outside his pants. He quietly whispered "You're killing me" I looked at him longingly and said "Tommy, you know I'm only 15" He said "I know I'm sorry" and moved my hand. I put my hand back and with the other hand I ran my fingers through his hair and said " It's not hurting anyone this will be our little secret. As long as we don't tell anyone we're fine" He said "Ok but no one means no one." I leaned in and kissed him again. I opened my eyes and said "One more kiss and I'm going to sleep" I kissed him slowly and then pulled away. After 10 minutes he was half asleep with his eyes closed his hands on mine. I sat up and said "I lied, After this I'll go to bed" and slowly kissed him again and again and again. I pulled away and said "Goodnight Tommy" And we both went to sleep holding hands. I woke up by 4 and let go of his hands so Sarah or her mom or sister didn't see it and suspect something. I'm 15 and he's turning 23 this August. I feel as though there's something between us. He only kisses girls if he's serious about them. (We were talking about relationships yesterday on the was to the concert) I want to be with him, but I'm so worried that I'll get him in trouble or something. What do I do? We both really really really like each other and I'm done with all the douche bag guys that are my age and he's done with all the girls his age that only want sex. How can I continue on our relationship?