Learning the rules is good, but try to put the focus on character - "what you want to do" not "what dice to roll." Each time, show them how it works (this is how attacks work, this is how magic works, oh please, don't tell me you want to grapple, etc.).

The ones more into pretend will pick up the rules more readily. The ones into rules will get past the fancy board game mindset.

And expect a lot of violence. Kids are scary.