There are many good answers here. There are multiple, well-documented benefits to walking. In addition to the article that Karin cited, here’s another good one from the American Heart Association: http://www.startwalkingnow.org/whystart_benefits_walking.jsp
Don’t listen to all the BS that walking is a waste of time because it’s ineffective for “torching belly fat” and all the other buzz phrases that are out there today. Some of it may be so, but there are still plenty of benefits to walking. It’s a great activity regardless of your fitness level – even if it just gets you out of the house for a while for some fresh air. It’s also a great reason to get (rescue) a dog if you don’t have one – everybody wins! Enjoy your walks Anne.