Date Picker Specific Date Ranges

<?php
/*
This snippet changes a datepicker option values for a specific datepicker field, edit the .input-field-dates to your specific form class names.

For installation instructions, please visit http://wp-events-plugin.com/tutorials/how-to-safely-add-php-code-to-wordpress/
*/
function my_em_datepicker_vals(){
    ?>
    <script type="text/javascript">
        jQuery(document).ready(function(){
            var date = new Date();
            //in this example, we're going back 19 years for a specific field
            date.setFullYear( date.getFullYear() - 19 );
            //.input-field-dates is a class assigned to the encapsulating wrapper tag around the date fields, check your source code for your specific class name
            jQuery('.input-field-dates .em-date-start').datepicker('option', 'minDate', date);
        });
    </script>
    <?php
}
add_action('wp_head','my_em_datepicker_vals',1000);