scribbling disaster

This morning, K. was sleeping so I got A. some crayons and her coloring book so that I could go take a shower.  She immediately said, "I can't do that."  A little confused, I persisted.  Again, "I can't do that."  So, I thought it was because she didn't want to stay downstairs while I was showering.  I stopped trying to convince her to do something by herself and simply asked why.  Her answer broke my heart.  To sum it up, she didn't want to color because a little boy at school told her she scribbled and didn't color.  So, I decided it was more important to color than to shower.  I tried to color sitting next to her with the idea that I would color and tell her what a great job she was doing.  Instead, she cried and cried and only wanted to color on top of the parts that I already colored.  Well, that wasn't going to solve anything so I wouldn't let her have my paper.  Apparently, I picked the wrong battle because she had a HUGE meltdown and would not touch the paper until we switched papers.  I then compromised by outlining the paper and letting her color in between.  She made the tinniest, tiniest marks in the center of the paper so that she wouldn't draw out of the lines.  Any time that poor little thing went over my lines, she had tears rolling down her face.  I was at a loss, and am still at a loss as to how to tell her that 3 year old little girls color outside of the lines.  She did finish her picture and I think it looked great.  Then we decided to draw in her scribble book, where she is supposed to scribble.  I don't know about her, but I don't feel better.  And, I want to scribble all over that little boy's face.  There you have it...