I was going to comment on the age difference issues at length, but I've rambled on enough. I did notice how DWJ used references to Polly's hair throughout: Tom starts off by admiring it and then mentions it in the one physical declaration of love near the end; Mr O'Keefe and David make remarks about how they'd thought about her and her hair when she was 15 or 16, and Polly completely ignores this. (Though maybe Ivy had a point about David!) But the best reassurance comes from Polly herself, who shoves Seb away and tells him she's too young for any of that. The age factor is probably more questionable in Laurel's pursuit of good-looking and musical teenage boys. Tom was 16 when she first went after him?

Finally, I found a Tumblr dedicated to DWJ, and it would have been her birthday last week:

http://dwj2012.tumblr.com/post/58417413636/today-would-have-been-dianas-79th-birthday