High school for me is hard, I have 3 Advanced placement classes which are the high school equivalent to college classes and a college class math, in my literature class we have a new book to read every week. How did you make the $40/hour?
...good you for, I had an A+ average, so what? ...I'm not going to tell you exactly, but it was a mixture of things - web design, domain trading, Adsense, website sales, etc.
If you live in the US, the answer is yes. By the way, you pay tax on every income you make. It's a no-brainer.
Tax is everywhere, we even got taxed when we rent a house and then rent it to others the second time, that's ridiculous.
From what I remember, if you make over $600 per year with Adsense you will be sent a tax form and must claim it. This is for USA residents