I'm really interested in Monero. I feel kinda nervous about using it, though, since even though everything I'm buying is legal, it feels like I'd be calling a lot of attention, and I want to make sure I'm buying and exchanging it in legal (if private) ways.

Using Monero is not much different from using Bitcoin. It's actually safer than Bitcoin in this regard, as you can't accidentally receive coins that are "tainted" by what previous owners did with them.