When we were in DC, I made a delightful trip to the National Gallery. As I perused the portraits in the Chester Dale collection (a definite win), and the rest of the museum, many of the little girls in the paintings looked familiar to me. After some pondering, I understood why: they reminded me of my sisters and myself! In that stage between babyhood and girl-dom -- toddler, is it called? -- we all had that same plumpness that translates so romantically into classical portraiture (except for in those creepy mini-adult baby paintings. . . those give me the heebie jeebies).
Maybe you can see what I'm trying to communicate (pictures are ordered from One to Five).