Sending email when a date count down is triggered - google-apps-script

Question

I am trying to set up a sheet with varying email address and
dates. when a date (due) counts down to 20 say, I'd like to send the
owner of the issue an automatic email. All info in in the same row
just varying columns. I post my semi-functional script here, I can get the correct line item to pull based on date, I just cant get the script to pull the associated email with the date. Or I get a ton of emails that i dont want. Sheet
Any help would be much appreciated!!
function checkReminder() {
// get the spreadsheet object
var spreadsheet = SpreadsheetApp.getActiveSpreadsheet();
// set the first sheet as active
SpreadsheetApp.setActiveSheet(spreadsheet.getSheets()[0]);
// fetch this sheet
var sheet = spreadsheet.getActiveSheet();
// Number of rows to process
var numRows = sheet.getLastRow()-1;
// figure out what the last row is
var lastRow = sheet.getLastRow();
// the rows are indexed starting at 1, and the first row
// is the headers, so start with row 2
var startRow = 2;
// Fetch the range of cells A2:B3
var dataRange = sheet.getRange(startRow, 2 ,lastRow,
sheet.getLastColumn());
// Fetch values for each row in the Range.
var data = dataRange.getValues();
//Logger.log(data)
// grab column 20 (the 'days left' column) changed numrow to last r
row
get last row change
var range = sheet.getRange(startRow,20,lastRow-startRow+1,1 );
var numRows = range.getNumRows();
var days_left_values = range.getValues();
// Now, grab the reminder name column
range = sheet.getRange(2, 16, lastRow-startRow+1, 1);
var reminder_name_values = range.getValues();
var warning_count = 0;
var msg = "";
//msg = msg + "Trial Reminder Trial: "+reminder_name+" is due in
"+days_left+" days.\n"
//for (i in data) {
// var row = data[i];
// First column
// var emailAddress = row[13];
// Recipe column (Priority HIGH)
// var message = row[14];
// var subject = "Reminder CAPA ";
//subject = subject + reminder_name;
// Loop over the days left values
for (var k = 0; k <= numRows-1; k++) {
var days_left = days_left_values[k][0];
if(days_left == 20) {
// if it's exactly 20, do something with the data.
var reminder_name = reminder_name_values[k][0];
msg = msg + "Reminder CAPA: "+reminder_name+" is due in
"+days_left+" days.\n";
warning_count++;
}
if(warning_count) {
//MailApp.sendEmail(emailAddress, subject, message);
Logger.log(msg);
}
}}