It is possible to learn calligraphy by yourself. However, it is not that easy to write well first, and it takes a relatively long time, and it depends on your own understanding! If you study completely on your own to reach a certain level, it will take at least ten years.
Participating in calligraphy training classes is the best way! Why do you have to explore it yourself again if you have experience? Wouldn't that be a waste of time and a waste of one's life?
The calligraphy class has professional teachers to provide guidance. The teacher will promptly correct problems that cannot be discovered by oneself. It only takes about three years to learn calligraphy through training classes and reach the same level.
In addition, self-study relies on perseverance and persistence. If you cannot guarantee the study time (practice calligraphy for at least an hour every day), or study every now and then, if you want to succeed, you will be far away... ..Wish you all the best!