Is my sister too strong?

My sister who is 13, is extremely strong. She's "iron girl" on YouTube, watch her videos and you will see what I'm talking about. I'm 15, and she can take me down! She can lift about 200lbs. Her biceps are 13.5 inches. I'm pretty athletic, workout 2 times a week. We arm wrestled and she beat me with Her 1 hand against my 2! I tend to be childish sometimes, and when I fight I tend to put people on the ground on there bellies with there hands behind there back in walmart hand cuffs I triped her while fighting one time, so I sat on her and put her hands in the cuffs and she was so pissed she broke out of them got me off her back and hand me on the ground. I'm afraid one day she will hurt me.