Walking is *great* exercise! It really is. You don't need to become a marathon runner to get results!
I used to walk to work and back daily, and walk just about everywhere else. I was lucky that I lived in a very urban area, and everything was fairly close by. I have now relocated for school, so walking is something I should try to be doing more of again!

I have to admit I have somewhat fallen off the wagon. But hey, I'm only human!
Although walking didn't improve my blood glucose control (exercise can cause more blood glucose swings and lows in Type 1's), it did help me feel more alert and fit. I didn't need to lose any weight, but I will point out that I was able to eat quite a bit and never gain weight while I walked regularly. Calories in...calories out! Exercise (including walking) has been shown to be a large factor in controlling Type 2 diabetes. It's very important!
I think walking is a great place to start for exercise. A walk after dinner can really help curb those after meal spikes.
Remember to get a physical from your doctor (including an EKG) before starting a new exercise program, *especially* if you have been completely sedentary, are overweight, and/or have heart disease or multiple risk factors for heart disease. You also should ask your doctor or Diabetic Educator about learning to avoid exercising when your insulin is peaking (if you take insulin), and how to treat low blood sugars. Also note that blood sugar may spike due to exercise. It's important to know that exercise can cause delayed low blood sugars and cause you to be more insulin sensitive for hours later. So you must not over correct any high blood sugars after exericse. For most Type 2 diabetics, these spikes will come down on their own. Type 1 diabetics may need to take a small *reduced* correction bolus of insulin. For the most part though, exercise normally *lowers* blood glucose levels, and you need to be aware of that. Also, any substantial weight loss will most likely require lowering your medication doses.
Anyway, this is probably more info than you wanted!
Basically, walking is a very good starting point, and yes, it really *can* make a difference. Any exercise is better than none, right?! Walking is easy, free, and can be fun if done in a group or with a friend. Or use it as your own personal "get away" time.
If you have joint conditions or are severely overweight, you may want to look into AquaAerobics. This will reduce the chance of joint pain and/or injury.
If you need to lose a lot of weight, walking is a good place to start. Once you begin to feel more comfortable with exercising, joining a women's fitness program such as Curves or at the local YMCA may help you reach your goals. The YMCA is much cheaper than Curves and many offer women's weight loss exericse programs. Even if you don't need to lose weight, walking is a great way to get and feel healthy. You *can* get into better shape and improve your glucose levels with walking if you really put in the effort. Win-win!
Wishing you well!