A lot of runners start their training program 16 weeks out and some think 12 weeks is enough time. The truth is, both plans will work just fine. There are a few secrets to making any plan work for you.
1. Nutrition - No matter what, eat healthy whole foods and get rid of sugar and process crap. This should be a no-brainer but it's amazing how many people will train for a race but keep going back to their tasty surgery treats or baked goods. The secret with this is to clean out your kitchen of all unnecessary dairy products, all those cookie, chips, and sauces that have a lot of sugar. Event some of those salad dressings too!
2. Consistency - When training and eating you have to be consistent in order to see the best results. They say if you go 3 days without doing any type of cardio then you lose some of your base. So keep up that schedule.
3. Mix it up - We all love variation. Try to throw in some variation to your training and eating plan. Granted there are those who need the same routine over and over and can do just fine. But for the rest of us, adding in some variation to your workouts and meal plans can really help make the training more fun.
Have fun with your training. Don't forget to drink water and stretch!
P.s. check out Nike's training program: