I will say that it's not too late, and that learning is always valuable. Now, whether you want to go to a school to learn, that's a harder question. In general, unless you're looking at jobs that require it, or you need the connections that a graduate program might bring, I wouldn't.

And don't worry about 'exponential' personal growth. Linear growth is still growth and it feels better to succeed at a linear goal than fail at an exponential one.