I am similarly "ambidextrous," self-trained as well. It started as a hobby in 3rd grade, so here's my anecdotal evidence that it is highly trainable. As for age

I am similarly "ambidextrous," self-trained as well. It started as a hobby in 3rd grade, so here's my anecdotal evidence that it is highly trainable. As for age, it is certainly a factor, but it doesn't make it untrainable. What I find more amazing is how people think it is unbelievable; I once felt like a circus animal in demonstrating it is possible to my friend. Everybody is "ambidextrous" (at least in regards to common motor tasks) to varying degrees. It's up to you to control this degree. A highly-trained violinist has a more functional left-pinky (more than the right pinky), for example. Another interesting thing about lefty and righty-ness, is that some people make the observation that lefties cross their arms and their fingers opposite of righties (e.g., left thumb on top for lefties). I reasoned that this was just habitual, so I deliberately changed mine, and over the years the "lefty way of crossing" is the most natural one.