At a Birthday Party

My long-time childhood friend AD has invited me today for his birthday party. I only see him once a year, he is already working at a job, has left school earlier. I feel completely displaced among his friends, do not know what to say. There is this girl on whom I had a crush in 1st grade, 12 years ago. She talks about her attitude towards sleeping with men, and that she just would not sleep with anyone on the first date. They talk about another girl who obviously has not such scruples.
I do not know what to say, so I just listen. For full two hours just listening, sitting in the corner, having nothing to contribute to the conversation. I feel liks such a moron.
Last night, after showing the pictures to my gang, I slept not very well. My thoughts were with B all the time. Why did I not approach her? Why did I not talk to her more? I was so distant.
I feel like I am falling back again, into my usual shy distant behavior that I have had all these years.

There is still a bot of snow outside, on the hill tops there must be more. The gang wanted to do cross-country skiing, but I had been at AD's party.
I feel weak and incapable.
Slowly life runs away.
I torture myself through it, I only want the best.
And I have really worked hard.
But not hard enough.
Yesterday evening would have been such a good opportunity like never again.
I have to make it.
But then, the dichotomy comes again. C appears. And I do not know what to do...
Why was the mathematics exam so bad?
I am disappointed, from myself and from them.