Sometimes you really need to take a look at your life and your friends and take stock. You need to do this whether you are "old" or "young" - I keep telling my kids that there is a reason that you have friends that seem to have been your friends forever and why you lose touch with other people through out the years. It doesn't make them or you a "bad" person its that one of you (or both) have finally realized the following.
There comes a point in your life when you realize:
Who never did,
Who won't anymore...
And who always will.
So, don't worry about people from your past,
there's a reason why they didn't make it to your future.