holcomb hiker

As I'm getting ready for a March start of my Thru-hike, I wonder if others are just as excited, anxious and afraid as I am. I've planned and dreamed of this for quite a while and as the start date gets near, my confidence level remains high BUT I have to admit there's some apprehension.
At 66 years old, I've remained fit and have been blessed with a good life and a great family so why am I leaving all this behind to hike the AT? The only answer I can come up with is that it's a challenge and I just want to test my endurance, both physical and mental.
I'd like to hear from others who might be "just wondering".