Full time worker and college student

This past summer I picked up a job full time, along with already being a full time college student. Keep in mind I am 20. Since, then I have had a gross income around 30k. I still live with my parents and attend school/work full time for each. However, they still claim me as dependent. While filling for taxes it says I owe almost 4000 dollars. I claim 0%. Does this seem right? I have never filled for taxes before so excuse me if I am making a simple mistake. Thanks