Just got a big female bp

[Kinra]

Also how long do I quarantine the new snake before introducing her to my male ball python? For breeding of course.

You should quarantine for 60-90 days.

If you really want to breed you need to do research first. You need to make sure the female is actually big enough, decide what you are going to do with the babies, make sure you have room for the babies, know how you will incubate the eggs, ect...

There is a lot to breeding and you need to know what you are doing.

Also the 20g sounds like it is too small. You should look into getting larger housing for the female since you can't keep breeding males and females together all the time, as I said before males will breed themselves to death.