Voice certificate is valid for 3 years. How old should I learn properly?

I suggest you start learning basic music theory at the age of four. Before the age of four, you can listen to various musical instruments and various types of music, and cultivate certain musical habits and cognition.

Music foundation is the basic knowledge of learning musical instruments, including simple reading of treble clef, bass clef, bar line, ending and so on. Only in this way can teachers carry out certain musical instrument teaching work.

Finally, I want to say that interest is the best teacher and persistence is the key to learning musical instruments.