When I studied abroad, my roommate and my American friends took a bath about three times a week.
I took a bath every single day at night so I kind of shocked about this.
Also, they don't wash their hair so often.
Is this normal?
I think most Americans would say they shower every morning, but it's not unusual to skip a day if we're running late. As for hair, I had to look it up. I don't wash my hair every day. This link explains how different hair textures need different care.
We don't have a culture of relaxing in a bath at night, for sure. Many homes don't even have bathtubs, just showers!