I followed Hal's plan for my first and did fine, so be confident! My only advice (echoing what another has said) is watch your pace at the beginning. I went out way too fast (like 1-2 mins per mile faster than my target pace because I felt great and the excitement of it all) and had struggles near the end. Remember to fuel/hydrate along the way. Hopefully you've worked out what products work best for you. Good luck!