Just no.... Yutaka is supposed to be cute small, and moe in a innocent way. (Miyuki, Yukari, and patty are that way)

Growth spurts are a bitch.

And this is the downfall of loli: when the lolicon realizes the little girl will grow up.

Thing is I don't think Yutaka will ever grow up physically much if any. (seems to have the same trait as Konata)