Full disclosure: I am a big Star Wars fan. But that doesn't mean one should watch Star Wars or anything else without discernment. All films have a behind-the-scenes agenda. For example, take George Lucas' purpose for the Star Wars movies. He wanted to use Star Wars as a platform to introduce Buddhism to America. The "Force" represents the impersonal god of eastern mysticism. You don't have to avoid Star Wars, but you and your children should be aware of its agenda. You should be able to articulate how using "the force" is different from how the Holy Spirit works in the life of God's people. The Holy Spirit's power comes from his membership in the Trinity and is distinct and separate from the power of Satan. They are not both using the same power source.
Lucas' vision for Star Wars fits with the perspective of eastern mysticism. The "force" is not personal – it is there to be used and manipulated by anyone, Luke or Darth Vader, for good or evil. It fits with the false idea of God being part of everything and not distinct or separate from his creation.