Imagine, if you will, a great big "X" directly underneath you. That's your NOW.
In order for you to get from where you were in the past, to where you want to go in the future, you must pass through that X. There's no way around it. You can't avoid the X, or run away from it, or pretend it doesn't exist... because it's you, right now, just as you are. The sum of all of the choices and happenstance in your life, up to this moment, good and bad, wanted and unwanted.
It's so seductively easy to become obsessed with that X. To pore over the things that you don't like about where you are right now, and to constantly analyze and scrutinize all of the things that did or didn't happen in the past. Oh how you wish they had been different. If only you had started exercising ten years ago! If only you hadn't entered that race and broken your ankle! If you only hadn't dated that loser in college who didn't want you to be on a sports team! Your mind can entertain itself endlessly, running around in circles like a dog chasing its tail, thinking of all of the could-have, should-have, might-have-beens that would cause your X to be way off somewhere else instead of where it is now...under your feet.
But therein lies the rub. Here you are, at your X. Whether it's exactly where you want to be or far from where you wish you were, You Are Here.
Embrace your Here. See it not as something to fight against, a summation of all of the mistakes and missteps of your past, but as what it truly is - a point in time, infinite in its possibility, and most importantly: temporary. The X of your now is fleeting, constantly moving as time keeps rolling forward underneath you. You (and only you) have the power to move your X in whatever direction you want, whether becoming stronger, or faster, or leaner, or more agile, or whatever. Obsessing over where you are now prevents you from moving towards where you want to be. Accept today, look ahead, and take a step toward your next destination.