withdrawal almost never works. so I wouldn't even try it. if his sperm gets in you at all you are highly likely to become pregnant. there's a ton of other forms of protections. There Birth control pills an condoms. if you do have unprotected sex or The condom breaks, whatever your reason may be, if you don't want a baby head to your nearest clinic AS SOON AS POSSIBLE(by the next day) and get the morning after pill. The last thing you want is an unplanned pregnancy. especially if you're a teen or in any form of education. most teen pregnancys result incompletion of highschool. if you look forward to a bright future of education and a good well paying job pregnancy really isn't for you. I'm not saying it's impossible to make it in life with teen pregnancy or unplanned pregnancy but chances are slim.
if you're an adult also I still wouldn't try pull out method. just be safe. unplanned pregnancies are hard no matter what your age may be. and it seems you don't want to be pregnant at the minute so just be safe.
If done correctly withdrawal is more affective than condoms but then again, most ppl can't do it right! I wouldn't recommend it. His pre cum might have some sperm from a previous ejaculation, he might not pull out at the right time, etc. There are just so many reasons why it would fail.