Complex sentence: By the age of twelve, she lead a group of girls to start their own 4-H Club and began selling pies, cakes, and cookies in the neighborhood of Chatman in Chicago going door to door.
Split into simpler sentences: By the age of twelve, she was leading a group of girls in the neighborhood. They started their own 4-H Club and began selling pies, cakes, and cookies in the neighborhood of Chatman in Chicago going door to door.