Try this one for current selection:
Sub A_SelectAllMakeTable2()
Dim tbl As ListObject
Set tbl = ActiveSheet.ListObjects.Add(xlSrcRange, Selection, , xlYes)
tbl.TableStyle = "TableStyleMedium15"
End Sub
or equivalent of your macro (for Ctrl+Shift+End range selection):
Sub A_SelectAllMakeTable()
Dim tbl As ListObject
Dim rng As Range
Set rng = Range(Range("A1"), Range("A1").SpecialCells(xlLastCell))
Set tbl = ActiveSheet.ListObjects.Add(xlSrcRange, rng, , xlYes)
tbl.TableStyle = "TableStyleMedium15"
End Sub