Google Sheets: how to print the first modification date of a cell

I would like to make a script that works like this script to print a timestamp when a cell was latest updated but in this case I want to go back when it was First Updated, not the last.

Here is an attempt:

function onEdit (cellOrigin, cellDestination) {
var s = SpreadsheetApp.getActiveSheet (); // Get the name of the spreadsheet
var r = s.getActiveCell (); // store the name of the active cell in the current spreadsheet
var cell1 = cellOrigin // This is the row I want to set values
if (r.getRow ()! = cell1) {// Ignore this row (where I put the dates)
var column = r.getColumn (); // Get the column # of the active cell
var time = new Date (); // Get the date and time of the last modification.
time = Utilities.formatDate (time, "GMT-08: 00", "MM / DD / yy, hh: mm: ss"); // Date and time format
SpreadsheetApp.getActiveSheet (). GetRange (cellDestination) .setValue (time); // put in time in the cell
};
};