Cool boxer

Your name was Lenka and you had one enemy... One day... He slapped you... And you didn't react... "Do you want a fight?" you asked, he answered "Yes, but you'll give up right away." You started jumping up and down a little, no one understood what you were doing (by the way, professional boxers seem to jump before the start of a fight, I don't remember the exact information). People gathered nearby, the fight began, you gathered your courage and punched your enemy in the face several times, he fell, and then you punched him in the stomach, he fell to the floor with a groan... You stopped and frowned at your enemy... By the way, you weren't a nerd, but a pretty good-looking girl, but no one knew that you were into boxing.