Take it from a teenager who hits Universal/IOA every weekend!: All kinds of girls (including some lookers) are ALWAYS at Universal!
Dora the Explorer, among other Nick Jr. TV characters, are always walking around at Universal Studios. Also, while some rides are predominately male (Men in Black, Mummy, Twister), the rides are unisex--the website edits the rides for all the crazy parts, but the experience as a whole is enjoyable for everyone. Each ride and show at Universal is packed with humor, enjoyable characters (whether you know them or not, like The Simpsons, E.T., Barney, Curious George, Shrek, Fiona, and the Nicktoons) and a fun little experience. Plus, it's a good place to go to just enjoy family time.
Meanwhile, at IOA, the rides are not about the characters (which are admittedly mostly male-oriented except for the Dr. Seuss characters and rides scattered around the lake), but about the experience. Think about it--it doens't matter if it's a boy or a girl, if you're screaming and having a good time speeding on a roller coaster or rocking around on a thrill ride, all that's important is that every gender is having fun. Did any girl ever complain about just a generic thrill ride? That's IOA
BOTTOM LINE: Take your daughter. Sure, more attractions are male-directed, but only a slight few. The experience is unisex, and fun for the whole family. (WARNING: Mummy, Twister, Jaws, Poseidon, and Jurassic Park are intense--think twice about those...everything else is safe.)