In Trouble or Not?

Yesterday, Taylor and Maddie were on the back porch. I allow them to play out back alone as long as they stay on the back porch where I can see them (and it is the only shady spot as well). Unfortunately my attention was on the television on laundry, dishes, vacumming, and scrubbing toilets and I didn't notice that they had found a small chunk of charcoal and were drawing on the concrete with it. I dragged them inside, yelling, and practically had to give them bathes in the middle of the day because they were so filthy. I was angry, I admit. Then, later, I noticed what Taylor had been drawing.

I asked her what she wrote, and she said "my name". How can you really be mad when your 4 year old daughter, who is not in formal preschool, was writing letters all on her own?