Issue concerning dates sorting - excel

Question

I am having issues to filter dates in a ListObject, as some of them get well sorted and others don't at all.
What I want exactly is to filter dates, take the one that is the closest to today and put it in an other ListObject (basically, the tool I am creating is a database where all important events are stored and I want to send the most recent in a ListObject). For the moment, in order to try things, I just put the filtered date in the column to the right.
Here is the a quick screenshot to explain :
So what I am doing is that I get the first column data. If I get the same reference multiples times, it means I have multiple events and I am trying to sort it using this code :
Sub derniereDate()
Dim i As Long
Dim j As Long
Dim lastRow As Long
Dim lastRowS5 As Long
Dim lastDate As String
lastRow = Sheets(2).Cells(Rows.Count, "A").End(xlUp).Row
lastRowS5 = Sheets(5).Cells(Rows.Count, "A").End(xlUp).Row
j = 1
For i = 5 To lastRowS5 Step 1
lastDate = Format(Sheets(5).Range("M" & i), "MM/DD/YYYY")
While Sheets(5).Range("A" & i) = Sheets(5).Range("A" & i + j)
If lastDate < Sheets(5).Range("M" & i + j).Value Then
lastDate = Sheets(5).Range("M" & i + j)
End If
j = j + 1
Wend
If j <> 1 Then
Sheets(5).Range("P" & i) = lastDate
End If
i = i + (j - 1)
j = 1
Next i
End Sub
Here is a screenshot of a case where the sort doesn't work properly :
Excuse me for my English, thanks for help and staying up for more details if needed.

Answer 1

Sub derniereDate()
Dim i As Long
Dim j As Long
Dim lastRow As Long
Dim lastRowS5 As Long
Dim lastDate As Date
lastRow = Sheets(2).Cells(Rows.Count, "A").End(xlUp).Row
lastRowS5 = Sheets(5).Cells(Rows.Count, "A").End(xlUp).Row
j = 1
For i = 5 To lastRowS5 Step 1
lastDate = Format(Sheets(5).Range("M" & i), "MM/DD/YYYY")
While Sheets(5).Range("A" & i) = Sheets(5).Range("A" & i + j)
If lastDate < Sheets(5).Range("M" & i + j).Value Then
lastDate = Sheets(5).Range("M" & i + j)
End If
j = j + 1
Wend
If j <> 1 Then
Sheets(5).Range("P" & i) = lastDate
End If
i = i + (j - 1)
j = 1
Next i
End Sub
Simply had to change lastDate type... Sorry for the useless post...