There are several things that you can, and should, think about as you prepare for your pilgrimage. The most important may be training your leg muscles to walk in the mountains (something they probably aren't used to), toughening up your feet to reduce the number of blisters you get in the first week, and learning how to read maps that are published in Japanese. Each of these will take work, but they are all doable with time.

Training & Your Feet
Reading Japanese Maps