''Stop yelling,'' Katie said.
She grabbed the bat and scowled at her brother. He scowled back.
      ''No girls,'' Sean piped up from pitcher's mound.
      ''What do you care? She's not on your team,'' Tom snapped.
      ''Sean glared at Katie for a moment, then shrugged. "Suit yourself. But I'm not going easy on her just 'cause she's a girl."
      ''Who's asking you to?'' Katie said. "Play ball!"

Bravo, VeraFaye!
Nicely done. It's all correct. I hope you will carry this lesson into your stories, as punctuating dialogue is on of the more difficult skills to pass on to young writers. Some have a natural ability to do it right, but some struggle.

Looks like you are off to a good start. :-)

I like how you are plugging along with your lessons. Only 4 left to go and you will have completed the course! Whoo-hoo!