Maybe because I grew up in a family of strong women I never thought it strange, but many of the books I read as a kid feature strong female characters. Eilonwy, obviously, and Rebecca from Terry Nation's Rebecca's World are very clear examples. One that's more subtle is Adara, the protagonists' mother in Power of Three by Diana Wynne Jones. Besides being the wisest and most competent character in the book, she's arguably also the hero of her own story, of which the protagonists' tale is only a smaller part. And when Garholt is attacked, she tries to physically beat back the attackers.