Updating the date value from an input field

Hello,

I’m wondering if there exists a way to update the date value the counter uses with an input field?

For example, instead of having the shortcode as such:

[countup date=2018/05/23][dtimer][/countup]

I would like to have something like this:

[countup date=”default”][dtimer][/countup]

Where default date is updated at the plugins admin page. Is this function possible/is it possible to create this functionality in the plugin?

Thanks for a great plugin and your support.