I suppose it don’t matter at all… http://tinyurl.com/do8d3 
damn . . . Click on the “hear Ciara play” button.
My primary teacher is 15+ years younger than I, but that just means he hasn’t reached middle age yet.
Well I’m not a very good at guessing ages, but I believe she’s about the same age as I am (25)… anyway she has lots of experience and it’s a great whistler, piper and fiddler
So I think you’re right, age doesn’t really matter
It’s customary for beginning students in almost any area to have younger, less experienced teachers. I know many of these teachers are very good. I have to say, though, that my two best beginner experiences (not in music) have been with fairly old extremely experienced teachers who were masters in their fields. It was just a strange bit of luck to get them and a strange bit of luck that they didn’t seem to mind teaching an absolute beginner. They took no nonsense, but would do whatever it took to help you understand something if you were willing to put in the effort. These two people actually affected my life and knew so many odd little helpful things that had come to them over, say, 30 years time. I wouldn’t say age itself mattered, but the amount of life experience and experience in a field could make a difference I think.
If someone is better than I am, they can probably teach me something … probably even if they aren’t better than me they could teach me something … actually, if they were even equivalent to me they could probably teach me something … actually probably … er … I got lost. 
djm
My last teacher is probably 20-25 years younger than me, but it didn’t make any difference to me. She certainly knows more about whistling than I do. The same group that she works with also has a young harp teacher that only takes kids younger than she is so no harp lessons for us middle-agers, sigh…