Yes you can do it Kristi!
I was once, not long ago, in your shoes. With over 60lbs to lose! It is such an easy concept that seems so overwhelming when first diving in!
Walking is going to be great for you! Combined with a healthy diet you will start to see you body change within a few weeks! I encourage you to vary the intensity of your walks, start at a pace you're comfortable with and each day/week increase your speed or incline to continue challenging your body for the best results!
I am sorry to hear about your husband but you have your whole life ahead of you, and you deserve to be happy!