Since you are so worried about pregnancy, the pull out method would be the wrong thing to do as it is not 100% effective, this is because you can still ejaculate small amounts unknowingly even before reaching an orgasm, this is called premature ejaculation and can result in pregnancy, this fluid often does not contain viable sperm but sometimes it does and it takes just 1 sperm to cause pregnancy so you don't wanna chance that.
I recommend that you ask her to look into fertility awareness, there are also apps which she could use to predict ovulation and the fertile window which gives an idea on days where you should abstain from sex (fertile days) and days where you can have sex without the risk of pregnancy (infertile days). However, it is not as simple as it seems and certain other routines should be practiced altogether to make this a very reliable method, such as taking basal temperature and observing changes in cervical fluids so lots of research should be done into this beforehand and the process of getting to know your body.
There are many apps that she can download for this such as Natural cycles, the flo app or any other basic ovulation tracking app
In your situation, its either fertility awareness, birth control pills or using a condom.