Just to add some clarity to the situation, income you received prior to your 18th birthday is no less taxable to you than it is now. If someone else is claiming you as a dependent, and your income was above a certain level, they would be well advised to report it and pay taxes on it, or they or you may be subject at some point to paying it with penalties and fees.
If nobody is claiming you as a dependent, then you should report your full income, and pay the appropriate taxes on it. Be sure to claim all your appropriate deductions/credits too.
Alternatively, and perhaps the best advice - seek professional competent advice.
Those of you who live in the United States, and use gambling losses as cover for your businesses would also be smart to realize that gambling online is illegal in the US, and could possibly have implications well beyond your tax liabilities. And of course, gambling losses are subject to a ceiling. I do assume you folks are a lot more clever than myself, but I just pay my taxes.