Oh ... and Caitlin Moran's book is excellent in parts and very funny, though bits of it are not funny and you quite probably wouldn't want your DD to read her graphic bits (description of abortion, etc.).
I also second "The Beauty Myth". Don't hate me. But nothing else by Wolf is worth a look.
I loved 'A Feminist Critique of Language' but it is not about everyday life activism.
Ariel Levy's "Female Chauvinist Pigs" is very, very good on the pornification of modern life and the widespread acceptance of this by women in the West. Extreme epilation as normal. Porn as entertainment. Blowjobs as empowering. Stripping as a way to pay for higher education.
I cannot believe there are 6 posts and no-one has recommended Cordelia Fine!
You're losing your touch, people.
Her book is Delusions of Gender - it might be a bit beyond her at 13 as it has quite sciency bits, but you will love it and it is written in a really nice, anecdotal style (with notes at the end telling you how the anecdotes are actually supported with real research!), so you could easily chat about it to her.