Why don't you write your gender and age on your resume?
The omission of gender and age in job resumes is mainly aimed at foreign companies, in order to avoid (prevent) discrimination and misunderstanding against women and elderly people in the workplace. So age and gender are generally not required. But in our country, it is better to write. Failure to write may make HR think that your resume is not standardized and unqualified. So it will be better to write it on Chinese resume.