Chinese baby gender Calendar.... true for anyone?

My husband and I really want to conceive a baby girl and we've been looking at the Chinese baby gender calendar to determine which month to try to conceive. I have tested most people I know for the gender selection and it came out right for everyone besides my mother (apparently I should be a boy lol) Anyways, wondering how accurate this thing is and if it's been proven to work for other couples. Thanks for reading!!