2001 Honda Civic How do I know if I need a new timing belt

I am about to drive across country from CA to NY. I went to have a 90K tune up and had my spark plugs and battery changed. I cannot remember if I've ever had my timing belt changed. The mechanic recommended it, in addition to my water pump and coolant. If my water pump isn't broke- do I really need to fix it? I'm short on cash and they said in total it would cost $400 to replace timing belt and water pump. Is there any way to know if my timing belt has already been changed (besides paperwork)? Thanks!