I want to be an officer in the navy, Will being in a mental ward for 4 days voluntarily ruin that?

I've heard that it can actually be a reason why the Navy would not accept me. I find this sort of shocking based off some of the former stoners from high school they have accepted. And I would also like to say that I also graduated from college with a good GPA, maintained employment and overall changed my life drastically since this period of my life. Honestly if you heard my story you would be quite impressed. I just don't want to be held back for something I view as a mistake. I don't believe the real greatness comes out of perfection anyway.