Wait.. What?

The last week has been absolutely stuffed with dance.  The recital for the studio that I teach at is this evening, complete with a teacher dance I'm participating in.  It's been a ridiculously busy week as I learn a hip-hop dance (while trying not to look like a chicken), get my girls ready, finish making and handing out dancer thank-yous, and help the director as much as I can with all the logistics of putting on a show with 100+ dancers.
Last night, right after the third run-through of our teacher dance, one of the other teachers approached me and asked me if I liked running.
Me- "About as much as I can- I've done a few 5Ks to try to stay in cardio shape, but nothing huge.  I'm kind of bad at running."
Her- "Oh, you've done 5Ks?  Perfect!  Want to run one for me?"
Me (in the post-dance happiness of a good run-through)- "Oh sure, no big deal!  When?"
Her- "Just the William Irvin 5K next weekend.  It's in the evening and no biggy."
Me- "Sweet, let me know the logistics whenever!"
Her- "Awesome!  Thank you, I was hoping not to waste my entry!"
It was only after the rehearsal was over and I was home eating a little post-dance ice cream that what I fleetingly agreed to suddenly sunk in.
I'm going to be running a 5K.
Next weekend.
During the annual Grandma's Marathon festivities.
Even though I haven't actually gone for a run in... weeks?  Probably over a month?

...Huh.

Well, at least I only agree to a 5K... right?