Tax for Google Adsense?

[Marky]

Google automatically taxes the income in the US so you do not need to worry about.

[Monkfish Bandana]

I am in the process of registering for Google Adsense to generate revenue for several websites of mine. I am 17 years old in full-time education. Several questions:

1. Do I have to register as self-employed?
2. Do I have to pay tax on my earnings from Adsense alone?
3. If no to the above, what age do I have to start doing this?