Advise Runnersworld complete guide to nutrition brill book & yes eating after once you get into longer runs is vital. Also depending on how far you eventually want to run or whatever your long term goal is runnersworld will have a training plan to suit. Good luck.
I did my first last October aged 43 & have now done 4, I ran upto 20 in training but I did a tough hilly twenty, you defo have the time but I would recommend having a look at a runnersworld marathon training guide. Good Luck.