You can teach yourself. If you are talented enough, you can become a master without reading music. There are many such examples, depending on your own goals. If you just want to play the guitar, you don't have to take classes, read books and watch videos yourself. If you want to take the professional road, self-study will be very difficult. When you reach a certain height, you will encounter bottlenecks. It needs some guidance, otherwise it will be difficult for you to pass. Anyway, it's up to you.