Let's face it, it's expensive to go to the movies these days. Few movies are worth your hard earned money, especially for a family. With that being said, I would definitely recommend you watch this new movie! Spring for 3D if you can. It's totally worth it.
The graphics and animation really lend itself to 3D so it's pretty cool to feel you're part of the action! Including the moment T-Rex is unleashed!
Also, you don't necessarily have to watch the first movie (Jurassic Park) to understand the storyline, but it is pretty neat to see the parallels throughout the film. It definitely shows how far we've come in modern day film. If you were a fan of the first, you will love seeing some of the same props used in this latest movie.