/kloc-can I get a health certificate at the age of 0/5?

You can't. Health certificate is a kind of certificate in the medical field, which is very useful. There is an age limit when applying, and you need to be over 18 years old to apply, so you are not allowed to apply for a health certificate at 15 years old. Health certificate refers to the proof of preventive health examination, which proves that the examinee has the health quality to engage in the prescribed business.