There is a lot of information about the legal status of Bitcoin.
https://www.irs.gov/newsroom/irs-virtual-currency-guidance

But if you can find a local dealer and sell your coins, do it. In a few years, we will have a clear situation on what is the best option for selling, buying and paying taxes for Bitcoin.
I some countries you can read clearly about it and already do the right moves, but in my country is still messy and there is not enough information about what we should do. I just go to the dealer and sell it. And no he is not registered or he is paying taxes, just a good old black market. For now...