The police officer who arrested you probably took your driver's license and gave you a temporary license (also called a "pink sheet") valid for thirty days.
To have any possibility of preventing your driver's license from being suspended, you need to request an administrative hearing at the California DMV within ten days of your arrest. If you fail to request this hearing, the DMV can suspend your license even if you are never convicted of DUI. When you request a hearing, you can also request a "white sheet" that will allow you to continue driving until the time of your hearing.
Regardless of what happens at the DMV hearing, you can also face a license suspension if you plead guilty or get convicted on your Ventura DUI charge in court. As a result, it is best to hire an experienced California DUI lawyer who can represent you both before the court and at the DMV.