Hi, my name is Julia and I'm 16 yo. I'm looking for a person who want to text with me in english, but I need person in my age or similar than it. If you interested let me know :))

Between "Who isn't?" and "Who doesn't?", "Who isn't?" would be the correct choice. You would use "do" for actions. For example, "Who doesn't act obsessed?" or "Who doesn't do that everyday?"

Who isn’t obsessed? Who’s not obsessed?