This is wonderful and I don't think age would matter here because ounce you become a Puella Magi it's a fact that your height and hair grow a bit. My friends said its supposed to represent that your growing up.
Strangely, it was Gretchen at the bottom that made me do a double-take. Smooth addition. The artwork's good, if their poses are a bit stiff, but it seems to be lacking something. The details are really nice though! I wish I could draw like this. XD