How does Maternity leave work?

I am currently 28 weeks preggers. i had my first daughter when i was 36 weeks preggers.
I informed my nurse requesting for maternity leave document to give to my Hr. Our company is new that sadly im the first one on the comp to get preggers so my Hr doesnt know what to do. she is new to our conuntry. i request to get maternity leave form from her cause thats what nurse said and she said back in my country we had 90 days maternity leave i dont know how california does it, ask your nurse for documents.

i have appointment this friday and plan on requesting forms from nurse.
just am concern cause im already 28weeks and had first daughter at 36 weeks which mean i may have a chance having my 2nd child in 7 weeks.

i rather be safe than sorry.
just concern and not sure how the process works.

i didnt have no work with first daughte, got laid off before preggers and hubby had job and told me to take it easy once we found out i was preggers.

first time im experiencing this while currently employed. esp at a new company that has no exp how to handle maternity leave...

would appreciate any information regarding this.

at the same time im concern if i did maternity leave i may leave 3rd week of dec which will place me at my 33week mark. nurse said if i did full term i should be expecting feb 5th.

also am concern if i did maternity leave early i may use up all 6 weeks and still be holding in my child not giving birth yet at 36weeks as my daughter was and perhaps may go full term.