1. First of all, I can definitely tell you that it is possible.
There are no high requirements for amateurs, they just have an interest in guzheng and cultivate their sentiments. However, for professionals who want to have a better development in guzheng, they can only rely on books. It is impossible to tune the strings or change the music in the paintings or DVDs. It would be much easier if you had a professional teacher.
Of course, in the end, the power is in your hands whether you study by yourself or find a teacher to teach you, so you can listen to my suggestions or study by yourself.
Some friends who love guzheng worry about whether they can still learn guzheng by themselves if they are too old. In fact, there is no age limit for learning guzheng. The key lies in concentration, diligence, and perseverance.