One can learn a great deal from a materclass simply through observing others being taught. When a class comes up simply apply to attend as an auditor rather than as a performer.
Meanwhile - and whilst acknowledging your stated reasons for not so doing - I concur strongly with those advising you to learn to read music. Age has very little to do with it. I have directed students in their seventies and older who have all progressed faster and enjoyed more music through engaging with notation.
It's not "easy" but it's certainly not rocket science either - so don't be put off - really, any fool can do it.
Juanito wrote:I really agree with Tormodg above, that a masterclass should have little to do with reading music.
Sorry to disagree Juanito but you're hardly in a position to be able to judge what a masterclass should or should not deal with. As it happens I have performed in masterclasses where my score was indeed presented in tablature - however, the conversation around the work pertained to music theory in just the same way as it would for notation.