VBA to hardcode value of checkbox when it is checked

I have a userform that has both Add mode and Edit mode. In edit mode, I am able to go in and make edits and changes as the project progresses, more specifically tracking when parts of the project are done via date/time stamp. However, I am having an issue with my date/timestamps. I have over 15 checkboxes that when checked it data/timestamps when that part of the project was done in the appropriate cell. My issue is that when I hit the command button "update" - it updates all the checked boxes to the current date. Can anyone help me in figuring out how to keep the original dates?