Don't blink, you'll miss it

When I was one I was just begun,

When I was two I was nearly new,

When I was three I was hardly me,

When I was four I was not much more,

When I was five I was just alive,

But now I'm six I'm as clever as clever,

So I think I'll be six now for ever and ever.

(A A Milne)

How did this happen?

From this...

to this...

I must have blinked.