Pulling out doesn't offer protection, so if you were ovulating you have a 20-25% chance. Unless you're wanting to get pregnant, you condoms at ALL times from start to finish.
You put yourself at such a high risk every time you have sex without protection, not only for pregnancy but also for STDs. The pull out method does not work, and don't forget there's pre-*** that comes as a risk factor too!
You might not be pregnant, but if you keep on having risky intercourse it'll eventually have an impact.