Check Date Format Input into Excel Column with VBA code ("DD/MM/YYYY" format)

Also, I need to validate it only 2 numbers for Date and 2 numbers for Month. and 4 numbers for Year. (DD/MM/YYYY)

What's wrong with the current code?
You are really confusing us, it only allows dd/mm/yyyy entry as you requested.

If you are not able to adjust the code, you should ask everything in the first place.

Private Sub Worksheet_Change(ByVal Target As Range)
    Dim rng As Range, r As Range
    Set rng = Intersect(Target, Range("M:M,T:U,Z:Z,AB:AD,AH:AI,CS:ST"), Rows("3:" & Rows.Count))
    If rng Is Nothing Then Exit Sub
    Application.EnableEvents = False
    With CreateObject("VBScript.RegExp")
        .Pattern = "^(0[1-9]|[12][0-9]|3[01])/(0[1-9]|1[0-2])/\d{4}$"
        For Each r In rng
            If Len(Target.Text) Then
                If (.test(r.Text) * IsDate(r.Text)) = 0 Then
                    MsgBox "Invalid date", , r.Text & " " & r.Address(0, 0)
                    r.ClearContents
                End If
            End If
        Next
    End With
    Application.EnableEvents = True
End Sub