I must have set up my account when I was 17 because my DOB is a year off. I'd like to have it right in case I need to recover my password/account. What's the easiest way? I couldn't find it anywhere in the PSN account settings online.
Short answer: you can't. At least, not with your account settings. Sony uses your DOB when you want to retrieve your password, and a few other things.
You may try to contact Sony, or at least the PSN department, but I would be surprised if they did.