Your credit score is a three-digit number representing your "creditworthiness" - it's like a grade that assesses your ability to repay debt. Banks and other financial institutions use your credit score to determine whether or not they feel confident lending money to you. Scores can range anywhere from 300 to 850, and the higher your score is, the more likely you will qualify for financial products at lower interest rates.
In the United States, credit is your lifeline to the financial system. Having good credit makes it easier to achieve important milestones, like renting an apartment, refinancing student loans, buying a car, or getting a mortgage for your first home. Conversely, having bad credit or no credit makes all those things harder.