That may not seem like a big deal to most folks but for me to walk 3 miles straight is awesome. Last year I could barely do a block without needing to rest, I couldn't stand for more than 10-15 minutes. It's my arthritis, I have bad knees...... Well I still have bad knees and my arthritis kicks into high gear during the cold, rainy days but now I am carrying less weight and my leg muscles and core strength have improved along with 98# less to carry around.
So start small, eat well and just move cause every day it will get easier and a year will go by before you know it. Then you will be doing things you haven't done in years or maybe even ever before.