Mike,
I agree completely with Joel. It is hard to do, (because you have actually been cheated out of good, fair, reasonable opportunities) but try not to think of what could have been and focus on what you can do now.
As far as bad association goes, I have a simlar story to yours, more academically than athletically, but what is bad association? Bad association is hanging around a bunch of negative, condemning people that tell you to look down on every other person in the world, other than themselves.......JW's. I know you said you consider yourself a JW still, and it may sound harsh to say that but, it is far more damaging to condemn than it is to condone. If you want to keep certain morals, great, do so. But we're all pretty equal in this big world and none of us have a right to judge others as harshly as the JW's do. The JW's, for the most part don't realize how spiritually limiting it is to be so negative to other humans that are really their equals, (I didn't 'till after I changed a lot of my previous close-minded thinking, so I know they don't know any better, either), but it is.
Focus on the positive.......... what you can become and are becoming, not on what you are not yet, or on what you haven't become. Take care and remember, you're fortunate to have open-minded people here who will give you good, fair, reasonable advice.
Brad