Mid-Life Crisis

I'm 41 years old, and I'm pretty sure I'm in the early stages of a mid-life crisis.  Obviously I've known about the concept of a mid-life crisis since I was a child, but the whole idea of it seems very cliche, and frankly, like something only the dads in movies went through.  Imagine my surprise when I found myself having thoughts and emotions that could well be classified as the beginnings of a mid-life crisis.  Here's what it means to me:  suddenly I realize that all of the "someday I might"s that I had in life just aren't going to happen.  At all.  I spent my life feeling like I could do anything, eventually.  I could travel.  I could live in different places.  I could try new jobs.  I could have different adventures.  Life was full of possibility.  There was always time, there were always options.  And now I'm figuring out that at this point in my life, the time for a lot of that stuff is just plain past.  I can no longer go through my life thinking maybe someday I will...I won't.  And accepting that is hard.  And makes me feel a bit panicked.  And sheds so much light on the cliches of buying an expensive car or adopting a whole new look.