I don't know if age ever played a factor for me. Almost universally, I liked the instructors with a Masters better than those with a PhD. I think the reason is because teaching was an annoyance to PhD's who usually view it as a distraction to their research, which is what really counts for them. The instructors with a MS were there only to teach.

It is probably not that way at a non-research university.

Not that I didn't have any great professors, I definitely did. My favorite econ professor was 25, on the other hand my favorite physics teacher was in his 70's and my favorite computer science instructor was in his 60's.