My cousin thinks she can beat me easily, why is she so confident?

She is younger, shorter and weaker than me. What makes her think she can defeat me so easily? She thinks it would only take her a few seconds to take me down. Is she dumb or somethingšŸ˜‚ She also wants me to fight her. What do you think? What should I do?
My cousin thinks she can beat me easily, why is she so confident?
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