Junior high school and senior high school really have little influence on your future work. If there is no other reason, you'd better tell the truth. Because if you fill in a fake one, you must pay attention to this problem in the future, and it will be bad if it is exposed. And this kind of thing, there is really not much possibility of counterfeiting, unless people don't care about this (that's even more unnecessary), otherwise you will know it when you look it up.

Also, whether you want to work or continue your studies has little to do with your previous experience (within the scope of the law). They are interested in your current strength and potential.