How to set a default empty value for DatePicker and avoid console warning?

[vim-diesel]

I am using DatePicker in a form, and am using state to control the value:

export default function MyComponent() {

     const [startDate, setStartDate] = React.useState<Date>();
return (
     <DatePicker date={startDate} setDate={setStartDate} />)
}

I want the default value of the date to be empty, so the user has to select a date. But if the user selects a date, I get a big warning in the console:

app-index.tsx:25 
 Warning: A component is changing an uncontrolled input to be controlled. This is likely caused by the value changing from undefined to a defined value, which should not happen. Decide between using a controlled or uncontrolled input element for the lifetime of the component.

I can avoid the error by setting the state as new Date() but that defaults it to today's date.

I don't want to set a default value for the state, because the user might pass over it in the form, since it is already filled out.
How can I leave it empty and avoid this error?

I am using NextJS with TypeScript and ShadCN, most recent versions

[vim-diesel]

it was actually a hidden input field I was using to pass the value to a server action, switching from an undefined value to a string. So this had nothing to do with the component.