If you look at worst-case scenarios, it can help...
Frank Lloyd Wright, America's most famous architect, had a few hundred designs that were never built. You look at most of them and they are so obviously the work of genius but they didn't go beyond the paper stage. When Mr. Wright was asked, late in his life, what his favorite design was, he would respond, "the one I'm working on now." He didn't lament, as his followers have, that some of his most incredible designs were not built. He looked to the present and the future.
If Van Gogh had tortured himself with the fact that he didn't sell any paintings (except one, to his brother), he probably would have stopped painting. He found joy and satisfaction in it and kept on.
If Frank Lloyd Wright and Van Gogh could keep doing what they were doing despite regrets of the past, I figure that my not going to the prom or dating boys or getting married and having babies is insignificant compared to their losses.
Or, taking a cue from the "road not taken" idea... So many of us have made mistakes in the flash of an instant. Think of the person who drifts asleep while driving and ends up killing someone. Again, their angst of that is far more horrible than my lament of not having a female past.
I know it's extreme to think of such comparisons, but it helps me get through the day.
Some of you mention being childlike.... My best friend (who is 3 years older) is someone who helped me go through transition, clueing me into female things. She became a mother to me in many respects. There is a pseudo-game we play almost all the time wherein she treats me like I'm her daughter. It gives me the freedom to act as a girl-kid. It helps me not lament the past because this game affords me the chance to LIVE today as a girl-kid. It's fun and it also gets me through the day.
Teri Anne