I am 59 and two years ago I picked up the bass and have been taking skype lessons and getting a good handle on it. Now, at the same time I am beefing up my guitar skills here and take lessons from a Roy Fulton in Ireland. Age has nothing to do with it! I am making more progress in these last two years than the previous 45 years! So, it is only a matter of putting in the time. I look at kids or teenagers who are really good. If they can get their chops up like that in just a few years so can I. And I have 45 years of experience to draw upon which they don't. 45 years years of listening they have yet to get. So, no problem. It is just a matter of being consistent, having a good practice plan, and putting in the hours. Nothing more. Age is irrelevant.