Do you know anyone . . . The person would now probably be 65 or 70
The oldest student I have taken on as a beginner was 84. What a darling. She took a 20 minute bus ride to get to me, I picked her up at the bus stop, we went to my studio, had a cup of tea to revive after the journey and then began to share music together. When I asked her if she had ever had lessons before she she said, "Oh no dear, no. We were far too poor to afford a piano. I used to draw a piano on a piece of cardboard and sit out on the verandah and pretend to play. Even now I do my best practice at night in bed!" This lady bought herself a piano and began lessons planning to be the best she could be - and she did achieve an amazing standard. OK, so she didn't get to play the Rach 3 but she did play well enough to sound fantastic and derive much pleasure from her music. I believe you can do anything you want to do, even though it may take longer than you originally thought! So adult beginners - go for it.