I have never sang in front of a crowd before and I am a tad bit shy... I'm not allowed to get a YouTube account and I don't have a video camera. I want to get to the top as soon as possible.

Well looks like you're onto a losing streak before you have even started.

Does you school have a choir where you could try out your singing in front of others, but without exposure you aren't going to have much success.

You are still very young and you have a long way to go. Getting to the top always requires hard work and commitment as well as full hearted dedication. If you aspire to be a good singer, take up music lessons and practice. Take part in your school choir and other activities which require you to sing. This way you'll be able to shed your shyness as well as work on your future as a great singer.

How many hours a day do you practice ?
Do you take music lessons ?
Do you take voice lessons

Are you in band or choir at school.

At 12 your parents are going to have to help you, they can set up a YOUTUBE account and put you on it, They have to take you to open mic and more.