Basically, we have to learn one of the main courses of mechanical engineering. We should learn mechanical drawing first, then mechanical design basis, tolerance and standard, material mechanics, mechanical transmission, mechanical design optimization, and then teach electrotechnics, metal technology and so on before we can learn other mechanical courses.

Learning CAD is only equivalent to first-year students learning to write. To be able to operate CAD (about the mechanical industry) at work, they must learn all the courses of machinery, because employers rarely only recruit CAD, but require mechanical skills, and will not ask you if you know CAD. It takes about a month to learn CAD until you can find a job (one class a day). If you haven't studied mechanical engineering, you can only draw what others ask you to draw.

The job you want to do is about to change your major, I hope you can think it over ~ ~ ~