How to assert today’s date or older in Cypress

I am trying to write a function in Cypress, where it loops through all the columns for my start date (#EventStart) and makes sure that the start dates are today’s current date or older. So for instance, I need this test to make sure that it is confirming that all the dates listed are either today’s date (April 4) or earlier (April 3, 2, 1, etc, etc). So far I can get it to confirm today’s date, but how can I add to the function so that it also looks for the days prior to today? Also, the way it is written, it is getting me GMT Time, how can I get it to display CST?

    public assertOldDate () {
    cy.get("#EventStart).each((el) => {
     let oldDate = new Date();
      oldDate.setDate(oldDate.getDate())
      cy.get("el").should("equal", oldDate);
    }
  }