The milage is about 37,000 mile. How likely the break pad need to be replaced?

There no such thing as 100,000 miles pads. It all depends on how each person drives. City driving will be less than highway driving. 37,000 is about average for brake pads. As brakes wear,it's normal for fluid to go low. Did they show you the brakes or did they just mention it? I have some customers come in and someone tells them they need brakes,but there only half worn. A lot of people will try to up sell work because there slow. Maybe get another opinion from another garage.