I backpacked and hosteled and camped and eurailed across Europe until i was about 40 - then i backpacked and eurailed and moved up to hotels.

never too old for backpacking and you do see some old fart backpackers there.

I would not avoid hostels because of your age. There are all types of hostels, some party places, some not.

That said, with two people traveling together often a simple hotel or B&B will be similarly priced and (to my mind) nicer.

Indeed, the HI hostels association even hawks a cheaper Senior card for elderly hostellers.

Only in Bavaria - 26 - is there a hostelling age limit and i'm not sure Bavaria still enforces this.