What do you think Peeta meant when he said of Katniss " she has no idea. The effect she can have"?

Peeta knows that Katniss has a power that affects people but she does not know it yet. Katniss is confused by this statement. Peeta knows that Katniss has the power to awaken people from subservience to the Capitol. She has a quiet charisma that makes people want to support her.