I thought this code was working ok, but just realized that if I select one item or a list of items, the first one is not listed. What am I missing?

Here's my code:
Dim I As Long
Dim X As Long
X = 13
For I = 10 To ListBox10.ListCount - 1
If ListBox10.Selected(I) Then
X = X + 1
Range("M" & X) = ListBox10.List(I)
End If
Next I