I have never been to Disneyworld, but there is a ton of other stuff to do there. Besides the main park (Magic Kingdom), there are several other parks/attractions, such as Epcot, Universal Studios, Animal Kingdom, Harry Potter World and many, many more. I have always heard that it's pretty much impossible to do it all in one vacation. It can also get very expensive.
I live 20 minutes away from Disneyland and have an annual pass. I love it. You can do the majority of the park in one day, especially if you're skipping the roller coasters. Right across the main entry plaza is California Adventure, a smaller park with fewer rides and several shows.
Both parks have opportunities to dine with the characters (not sure if she's too old for that to be fun), fireworks shows, lots of shopping, etc.
If you choose Disneyland, there is a ton of other great stuff nearby too. You are within 30 minutes of the beach, a water park (if you go in summer), great children's museums, shopping, and more. You're also about an hour away from Legoland and Universal Studios (in opposite directions of each other) and about 1.5 hours from The San Diego Zoo, Wild Animal Park and Sea World.
Honestly, I don't think you can go wrong with either one.