Honestly, I'm just curious and interested to know what age Wendy Darling met Baelfire and what age she was when she left to go to Neverland for the first time? (Obviously I don't mean what age the actress was when she played Wendy, I mean the character)
Clearly she's a teen, and it seems as if she is of a similar age to Baelfire - who at the time, (I think) was 14? Because Baelfire turning 14 and Rumpelstiltskin becoming the Dark One all happened within that year, along with the whole falling into a portal into the Land Without Magic aka England.
So basically, Baelfire meets Wendy when he's 14.
Consequentially, what age is Wendy, and her two brothers at this time?
It's never stated in the novel, either, but it's generally assumed that she's around 12 or 13, as her father makes a statement about moving her out of the nursery, saying she's too old to still be there.
Ages aren't given for her brothers, either, although Michael is basically a toddler and John seems to be 9 or 10 ish.