How long it takes for someone to learn to play the piano truly depends on the individual for a variety of reasons. Anyone can learn to play the piano, but some people tend to have a natural talent. That natural talent, however, is far from being the only factor that decides how long it takes for someone to learn to play the piano.
Age can be a factor. Younger people’s brains are like sponges, and that enables them to learn an instrument more easily than adults. Think of it in terms of learning a new language. While that is the case, adults can certainly learn how to play the piano, but it may just take a little more time.
Adults are saddled with additional responsibilities, too, which leads to the next factor. The old adage that practice makes perfect might technically not be true, but the more you practice, the faster you learn. Practicing daily or as often as possible throughout the week is key to learning to play the piano faster.
When I learned how to play the piano, in less than two years I was part of a group performing professionally in churches. Initially, for even the first few months, it can appear that the learning process is slow moving. There is a lot of technical information to learn and process. All of the sudden, however, everything comes together and you start playing all kinds of pieces.
How fast you learn also depends on the teacher. I had a great piano teacher. After two years, she told me that she had taught me everything she could teach me by that point. Learn how to play the piano, get ready for an adventure, and see how far it takes you. The piano is a beautiful instrument, sight and sound, and it is going to take you places one way or the other.