Date pickers should start on Monday instead of Sunday

Question

I have a custom widget for date input:

class JQueryUIDatepickerWidget(DateInput):
    def __init__(self, **kwargs):
        super().__init__(
            attrs={
                "size": 10,
                "class": "datepicker",
                "autocomplete": "off",
                "placeholder": "Select date",
            },
            **kwargs,
        )

but when I open date picker, it starts from Sunday, like: Su, Mo, Tu, We, Th, Fr, Sa. Can I update it to start on Monday? Might it be solved adding some JS or JQuery code to my base.html