I've also started reading Marathon: The Ultimate Training Guide: Advice, Plans, and Programs for Half and Full Marathons.
I love this: "In a marathon, except at the elite level, you do not beat others, as you might in a mile or a 100-meter dash. Instead you achieve a personal victory. If others finish in front of or behind you, it is only that their personal victories are more or less than yours. A person finishing behind you with less talent or of a different age or sex or various other limiting factors may have achieved a far greater victory."
One exciting possibility about my marathon training is that I will have a lot of personal victories along the way. Today, I ran 6 miles faster than I have before. It was 75 degrees and 90-some percent humidity. I felt awesome. In a few weeks, I will be running father than I ever have before. I'm excited for this process and these opportunities.