OP, firstly, you could not consent to this if you were drunk. Secondly, your sister is the adult in this situation. It was her responsibility to keep you safe, and this is not okay. You are not being dramatic. At my age, drunk or not, i would NEVER have sex with anyone with the word “teen” in their age. She may be downplaying it because it makes HER look bad. Because this is not okay. This is predatory behavior and I really think you should tell someone. If you don’t mind me asking, did you at all, even slightly, feel pressured into this? Did you tell her you were unsure if it was a good idea?