Adsense is restricted to 18+ technically.
The trick to making money is.....
(buy my $97 ebook
)
SPENDING MONEY.
I'm 15 also, and I know firsthand that the only way to make money is to have seed money. Get over yourself, invest $100 in stocks, take the earnings from that and buy some server space and Wordpress.
Also...if you are asking that question..why the hell would you want to start a Make Money Online blog?
Jason