Google Sheets Script to update a timestamp if a field in the row gets updated

Update SwissMarches Character Received XP

function onEdit() {
  updateSwissMarchesCharacterReceivedXP();
}

function updateSwissMarchesCharacterReceivedXP() {
  // enable/disable debug mode
  var debugMode = false;

  // definitions
  var sheetName = "Player Characters";
  var startRow = 2;
  var xpColumn = 13; // "M" column
  var updatedColumn = 17; // "Q" column

  // get the current active sheet
  var activeSheet = SpreadsheetApp.getActiveSheet();
  
  // check the current sheet
  debugMode && Logger.log("active sheet: "+activeSheet.getName());
  if (activeSheet.getName() !== sheetName) {
    debugMode && Logger.log("doesn't match our sheetName: " + sheetName);

    return;
  }

  // get the current cell (and row index)
  var cell = activeSheet.getActiveCell();
  var curRow = cell.getRowIndex();

  // check the current row
  debugMode && Logger.log("current Row: "+curRow);
  if (curRow < startRow) {
    debugMode && Logger.log("curRow < startRow -> exit");

    return;
  }

  // check if we're in the XP column
  debugMode && Logger.log("current Column: "+cell.getColumn());
  if (cell.getColumn() != xpColumn) {
    debugMode && Logger.log("cell.getColumn() != xpColumn -> exit");
    return;
  }

  // set updated at
  debugMode && Logger.log("set updated at");
  activeSheet.getRange(curRow, updatedColumn).setValue(new Date());
}