RE: I just couldn't do it.....
Don't shoot anything that you will regret later. Walking up to a mistake on the ground is tough and unlike fishing you can't "release" it. I saw a fawn with spots on Saturday and no doe to be seen. December is a fine time to take the does. They tend to be concentrated at food sources and that makes it easier to pick out "grandma". It sounds like you made the right choice for you. That is what matters.