The things we do outlast our mortality. The things we do are like monuments that people build to honor heroes after they've died. They're like the pyramids that the Egyptians built to honor the pharaohs. Only instead of being made of stone, they're made out of the memories people have of you.
The best way to measure how much you've grown isn't by inches or the number of laps you can now run around the track, or even your grade point average-- though those things are important, to be sure. It's what you've done with your time, how you've chosen to spend your days, and whom you've touched this year. That, to me, is the greatest measure of success.