Personally, I don't think it's shameful. If you really haven't studied, you can write "none" in your academic qualifications. What matters is not how high your education is, but whether you are honest.

I told you, you must write realistically. In fact, you can fill a gap in the situation. Examples are as follows

If there is only a primary school diploma: fill in the primary school.

If there is only a high school diploma: fill in junior high school or high school.

If all your diplomas have undergraduate diplomas: fill in the undergraduate course.

If you don't have a diploma: fill in none.