Personalized I'm Seven Years Old with Dog and Mouse Baby Bodysuit. Celebrate your birthday with Dog and Mouse, the unlikely best friends from the children's book "Dog and Mouse" by Michelle Nelson-Schmidt. I'm Seven Years Old with Dog and Mouse Baby Bodysuit - Heather and Hot Pink, perfect for young readers, helpers, and great friends on their birthday. Our one piece baby bodysuit make great gift for newborns, babies, infants, baby showers and expectant moms. An ideal gift for any new parent who will want one in every color.