Training advice? Don't give up, don't ever be intimidated, and ask for help.

A wise cat 1 once told me a great piece of advice i will paraphrase and take a little bit out of context....

Racers lose races when they lose control of situations. To practice I would recommend trying to identify situations to put yourself into and learn how to maintain control in them. Never ridden in a group? go ride in a group. Never ridden in the rain? Go ride in the rain. Never ridden a century? Go ride a century.

I started cycling at your age as well and looking back on it the main thing is trying to keep it fun. Set realistic goals. Don't try to be the next Lance...try to be the first you. Decide that you'd like to be a cat 3 and then start to figure out who you could do that. What events would you have to go to, what kind of placings you would have to have. Compare that to what you have experienced to get a sense for what you need to do.

Try new things. If it doesn't work for you then now you know.