You do not technically need to get an individual policy as soon as you reach college age. Most of the time, it is a better idea to stay on your parent’s plan until you are more financially stable or reach an age where you are not allowed to be on it anymore.
You might need your own insurance if you were in previous accidents, as it would greatly impact the cost of your family’s plan. In cases like those, you would want to consider getting on your own plan.
However, the situation varies between students. You will want to talk with your family or the person responsible for handling the car insurance at home. If you do not need to be on your own plan yet, it would benefit you greatly not to make the switch.