Tortoise poop at my door

I just got a desert tortoise that just came out of hibernation (barely). She seems nice and all, and I've been introducing her to my nieces and nephews. They've been gentle and respectful. So why is it that she took it upon herself to leave shat at my door? Is this normal tortoise behavior. Is she mad at me? Is she mad I woke her up? Is it possible to potty train a tortoise?