Ummm... No? That was literally what people have done for decades? Is the implication that you feel you are too old to read a book at 45 and start programming?
Sure, you will make hundreds of unintended decisions along the way that a seasoned developer would scoff at (for good reason), but a functioning first application in half a year when learning on the job is exactly what people have done, always. Is it a good idea? Well, it is always better to have a professional at hand to help and do away with the beginner's problems from the beginning, but it's absolutely doable.
Programming is not a black art, but something anyone with a bit of logical thinking can pick up from a book. Hence the "Learn yourself Java in 48 hours" books the were so popular for a while.