Hi Chelley. All the info you've been given is good. However, I'm going to turn this into a different direction. You say you "eat healthy", but have given no description on what that is. You can ask 10 different guru's and they will give you 10 different answers. I like thinking in generalities, rather than on specific "diet plans". True, calories do count, it's a matter of physics, but so do the biochemical aspects of those calories.
Here are a few articles you may want to think about and compare to what you are considering healthy. Also read the nutrition secton on this site.
http://www.johnberardi.com/articles/nut ... habits.htm
http://www.johnberardi.com/articles/nut ... ting_2.htm
Let us know how you what your diet looks like, and we can go from there with diet and exercise advice. Adding some weight training to your walking and diet will really benefit you.