This is the sentence that made me think George must be so much younger than his brother: George is almost a new acquaintance to me, and I find him in a different way as engaging as Edward. To me that reads like he's young, so his personality changes so much each time she sees him (like when you see a child when they're 2 and the next time they're 4 - it's like a different child!). I wonder why she doesn't know George as well?