I was 17.  It was with my now-fiance.  We'd gotten close over the summer when we were in a play together.  after school started, and I was in another show, he was working concessions for it.  He and I would hang out during Act II outside (I was in only 2 scenes in that act so I had lots of down time).   We danced around the kissing issue, but it didn't happen.
He drove me home from the theatre that day and we sat in my driveway talking.  He asked if I maybe wanted to do something sometime (translation: will you be my girlfriend?).  
Before he left, we were hugging, and he pulled away and kissed me.  It was perfect.  
