each passes into your function index and element. Check index against the length of the set and you're good to go:
var set = $('.requiredText');
var length = set.length;
set.each(function(index, element) {
thisVal = $(this).val();
if(parseInt(thisVal) !== 0) {
console.log('Valid Field: ' + thisVal);
if (index === (length - 1)) {
console.log('Last field, submit form here');
}
}
});