Which Backpack for Preschool? (VIDEO)

We have received quite a few emails with the same question.  Which size backpack should I get for my 3 (or 4 year old) who is going to preschool?  While the smaller toddler backpacks are adorable -are they good for preschool?  And while the larger ones will hold more – are they too big for my little guy?  Here is my answer: