To half-marathon or to not half-marathon?

from thatsfit.com

My sister's friend is training for a half-marathon in February. She wants my sister and me to do it too. So my sister drove up my driveway the other day, called me on my cell phone, and beckoned me to her car window where she handed me this Hal Higdon 12-week training plan intended to prep me for conquering 13 miles, all in one shot. This is the same me who has only ever run as many as five miles at one time. My long runs lately are three miles. Hal's training schedule features three miles as a short run. I'm not sure about all of this. Either is my sister. More