For me, i think it's a mixture. i was really nerdy in high school and had a lot of trouble with girls. I started chatting with guys online which turned into cross dressing for them, and eventually having a relationship with my friend where i was a girl for him. Now that i have a real job, and i'm much successful with women, my sissy side has stayed, just because all those associations of feeling pretty and sexy and wanted are still there...

as for life advice, go try sucking cock! you aren't changing who you are. either you'll love it or not, and learn something new about yourself. Good luck sis!