One step at a time.
PMCs like Blackwater are blooming because of conflicts like Iraq. Once that fizzles and people pull out, there isn't really much we can say in what will happen to that job market. It probably will be silent before another kind of Iraq happens.
Just plan on being in the military.
If there's a big war that will last a long time (hard to predict by the way), PMCs are hiring and you don't think you want to continue to serve in the military for a long time, then think about going PMC.
Also make sure you got a lot of good experience behind you. Also there are many kinds of contractors. Look up what kind you want to be.
But for now, I'd say shelve the whole PMC thing and focus on being military.
Remember dude, life changes a lot.
Even three months ago I was SURE I was going to make a career out of the military. Now it's not so certain because my life is a bit different now. THe same can happen to you.

Easy-8, good on you for being able to take instruction. This bodes well for your future in the military and life.