I suggest volunteering as an intern at a local studio. Starting at zero, you're going to need a whole lot of information and going to studio for a few months is probably the best way to get the basics.
Then, attempt to record a band on your own. I started with a 4-track, but these days you might want to jump right into Pro-Tools. Maybe the studio you were working at would let you use it on an off day to record a high school band or something?
Nothing will teach you faster than making all the mistakes. Any "experienced" engineer made them all when they were starting out.
To answer your question about compression: A compressor narrows the gap between the peaks and lows in a waveform. It can do this by bringing the lows up, or by bringing the peaks down (usually called limiting). Play with one and you'll hear what's going on.
