Time is not on my side

Sitting here, staring down the last day of school and wondering, as always, where does the time go and can I please have some of it back?
The year has three major points — first day of school, Christmas break and last day of school. Everything else is sandwiched in between; just one, long, dizzying blur that speeds up and slows down at random. It's a real life version of the whirling thing in the playground that you spin and hop onto.
One moment, I'm knee-deep in diapers and bedtime chaos. The next, our last child is done with fifth grade.
After 13 years, we have no one left in elementary school.
Part of me thinks that when fall arrives, I'll just keep walking down the block to school even without a kid in tow.
The next one up is heading into 8th grade (on the verge of high school!) and the one after her will be in 11th grade, one year away from graduation. The oldest is done with her freshman year in college.
Who needs to look in the mirror? These kids are a continuous, looping reminder that I am getting older ... every minute of every day.
At what point did I really think that having kids would keep me young?! Whatever that magic was has stopped working.
Worse yet, they think I'm old, not cool. My jokes are not funny. I should not sing out loud. No longer am I at the center of their universe, but rather some fading light in the nighttime sky.
I know they mock me, even though they insist they are not. I can see it in the roll of the eyes and hear it in the heavy sighs.
Can I really be two steps away from the nursing home?
The only consolation is that this will come full circle. I know. I did the same thing to my parents.
The only difference is, of course, I am so much more cooler than my parents were.