You likely owe because the tax being withheld from your paycheck is not enough to cover your total tax liability each year. The less tax that is withheld during the year, the more likely you are to end up paying at tax time. I would suggest that you adjust the amount being withheld from your paychecks. The IRS has a tool that will help you get a refund next year: IRS Tax Withholding Estimator.

Follow this link for more details: Why would I owe federal taxes?

Because you have no dependents and are under 25.

Child dependents get you the big tax credits. Single people, under 25, without children, are not eligible for the Earned Income Credit.

You also didn't do enough withholding.