Why does my friend think she is my mom?

like im actually in shock as to how she is treating me. she thinks she is this chill undramatic girl but she is exactly the opposite. i had my english final yesterday but i didn't go because i had a crisis with my family the day before. my family and i got into a huge fight, the biggest one ever, and i couldn't do any of my work because i was banned from the computer. well after i didn't got to my final, my friend goes "omg you didn't go? thats so rude to the other kids in the cl honestly" and i felt like i was being attacked so i stood up for myself and said, "um no, actually it'd be rude to me if i went and failed so thats why im making it up tomorrow" and she starts like yelling and saying stuff like "you think you can do whatever you want but you cant" i completelely 'owned' her in the argument maturely and nicely and she knows it. she can't stand to lose anything so now she is being so rude. like "why aren't you at em's b-day party yet ur late?" is she kidding??????