Add Todays Date When Cell Value=Y (but Not Using TODAY Formula)

I’ve been searching the forum but am struggling to find exactly the information I need!

I’m trying to get a column of cells to update with the date that the cells contents change to “Y”. I had been using the formula =IF(I7="Y",TODAY(),"-") in cell J7 but this updates the date every day. I need this date to remain the same as when it’s first populated.

I’ve been trying to cut and paste text from existing posts into the Visual Basic code but am new to this so am not getting the results I need. I had tried:

Private Sub Worksheet_Change(ByVal Target As Excel.Range)
'will put date in column B when something is put in A
If Target.Column = 9 Then
Target.Offset(0, 1).Value = Date
End If
End Sub

But this caused all sorts of problems! I then tried messing around with:

Option Compare Text
Private Sub Worksheet_Change(ByVal Target As Excel.Range)
On Error GoTo enditall
Application.EnableEvents = False
If Target.Column = "I" Then
If Target.Value = "Y" Then
Excel.Range("J").Value = Date
End If
End If
enditall:
Application.EnableEvents = True
End Sub

But this doesn’t work either. In fact, both these codes are probably riddled with errors as I’ve been trying to learn by trial and error!