I think you're smart to go about
this as you're doing. I don't know about
you, but I tend to go overboard sometimes when I start a new exercise regimen or something similar. It's easy to let our enthusiasm carry us too far; then we overdo it and later pay for it. But you sound like you're determined and being very sensible in the way you're doing it, and I think that will help you to succeed.
I get more of a weak feeling in winter, and have to pull myself out of it by adding exercise. It sure isn't easy to do that! I'm slowly working on more exercise also. Step by step, I think, is the way to go.
Hope you keep us posted!