Not necessarily. Generally speaking, having this certificate will help. But this is not necessary. As a primary school girl, I went straight after graduating from high school. Of course, I have had a short Korean training, but it is definitely the most elementary level. If you study in Korea, choose a good school and have more contacts. The school will arrange for you to go to a language school, and then determine the length of your time in the language school according to your language level.