Scared of the Dark

So lately I have been encouraging Pearl to learn to do simple tasks on her own. I wanted her to try to put her shirt on this morning. She put the shirt on her head where it got stuck for a few seconds before her head popped through. In those two seconds, she burst into tears and cried for several minutes after. I thought she was crying because the shirt was squeezing her head but she said she was crying because "it was dark in there!!". She also refuses to close her eyes during prayers because "it is too dark."