It's been a few years since I've worked on protools (I use logic now)... in my experience, though, you should be able to catch the basics of protools pretty quick, if you are motivated... and having your band breathing down your neck is a great motivator. Just don't be afraid of it... and the fact that you understand a real-world mixer is a big leg up.
Know, though, that you WILL become very well versed in all the frustrating vagaries of computers and audio and interfaces. The steepest learning curve isn't the software, but in the technicalities of getting sound in and out of it. You will do lots of troubleshooting, forum-lurking, hair-pulling, and head scratching. And you will blow at least one recording session, spend eight gruelling hours trying to figure out some arcane problem, be ready to throw your computer out the window, only to learn the next day that the problem was one un-ticked checkbox three layers deep in a preferences menu. Plug and play is still a myth as far as daw's go. But don't let that scare you off... just be prepared for it.
I would echo the suggestion to check out the other offerings as far as daws and interfaces go. The other daws (logic, dp, etc.) were a little harder to learn than protools (for me anyways) since all the midi and looping functionality can be intimidating.... but I'm glad to have learned Logic because midi is sooooo much fun, even though I never thought I'd use it.
I like protools a lot, but moved away from it because I found their support was lacking and the early m-audio stuff was getting questionable reviews, and I personally don't like the way digidesign traps you into their software/hardware and ransoms you for upgrades every couple of years... it seems like they might have come around a bit since I switched, though.
