Why does Grandma's Marathon freak me out?

I said that I’d elaborate on why I’m nervous about Grandma’s Marathon so here I go:

1. It’s GRANDMA’S marathon, the one that I’ve trained for 2 other times and failed. In 2004 I went out for my 17 mile training run with Marty and found myself unable to finish because of foot pain that I couldn’t push through. It turned out to be a stress fracture and I couldn’t continue with my training. The next year I tried again and stopped training pretty early on because I got busy, fell off of my training schedule and got discouraged. I ended up doing the marathon, but it wasn’t pretty. No running for two months followed by a marathon= extreme pain and a 6 hour and 22 minute adventure that I vowed to NEVER repeat
2. The last time I did the marathon I stopped running for 5 years. After the marathon I felt like I deserved some “time off.” I wasn’t able to pick running back up again because I always felt anxiety over the time commitment.
3. Figuring out when to fit in my training runs. I’m scared to run in the dark by myself.

Enough with the excuses here are the reasons why I think I should forget everything above:
1. I love the feeling after a long run; it really is a “runners high.” Nothing beats the feeling of walking around on “runned” legs during the day.
2. I want to be a role model for our kids
3. I want to join Marty in an active lifestyle instead of always cheering him on (although, I do LOVE cheering for him).
4. I want to lose a few pounds and get back to ideal weight—running allows me a treat every once in a while that I wouldn’t get without the miles.
5. I love the feeling of being fit enough to go for a casual 10 mile run for stress relief.
6. I really like shopping for workout clothes (yes, Marty I really am listing this one). If I run I’ll need clothing so this is a good way to justify :)

What I’ve already learned about myself:
1. I love training schedules and they motivate me however I can’t use them as a crutch. This time around I need to accept that I can’t always follow the training schedule and I need to be flexible. In the past any deviation in my training schedule has discouraged me so much that I’ve stopped training. I’ve proven that I can do this without training, so any training during the last 2 months will be better than my 6:22 marathon.
2. I’m not used to the quiet time with myself. For the last 5 years I have been with someone all of the time: if I’m at home I’m with kids, in the car I call someone on the phone, at work I’m managing people. Basically I never take time to reflect and running gives me this outlet. It’s actually been a little scary; I don’t know what to talk to myself about….

I’m sure there’s more, but this has been the conversation in my head while running for the past week….