Just because you live in your parent's home and drive their vehicles does not automatically mean you are covered to drive their vehicles. They will need to let their insurance company know you are driving their vehicles and that you are licensed.
Chances are, you will need to be rated on their policy as an eligible driver - if you want to be covered to drive their vehicles. Most all insurance require that the policyholder lists all licensed household members on their insurance policy as drivers. So if your parents do not inform their insurer of your licensing status and that you are driving the cars then they are running a serious risk of their insurance company denying a claim if there is an accident. Also, it will be up to your parents to decide if you should have to pay any insurance premiums since likely their rates will rise to add you to the policy, especially if you are a newly licensed driver.
If adding you to their policy increases their premiums, they can come here to get a car insurance quote to compare their rates.