I am 65. Does this mean I cannot stay in a hostel?
Most hostels have no upper age limit. Bavaria is one region that does have a limit. Check out the Hostelling International website for some FAQs on staying in the hostels that are members of Hostelling International.
http://www.hihostels.com/web/a-faq.en.htm#150
While many of the people who stay in hostels are in their 20s, you will see families and people of all ages in hostels.
Joan,
You can most certainly stay in Hostels (except for the exclusion mentioned in the previous post, although I've heard that some independents in Bavaria don't follow that rule)! I've encountered people of all ages in Hostels.
I normally use the "chain" Hostels such as HI, and have never had any issues with age (I'm mid-50's BTW).
Happy travels!