Clarification may be needed as to what exactly you want, as 'A' refers to columns, not rows
The 'Home' key will move the cursor to column A whilst remaining in the current row (or the topmost selected row if more than one row is selected).
'Ctrl +Home' will move the cursor to the top left cell, A1.
If neither of those are what you are looking for, the only alternate arrangement that I can think of is using 'Ctrl + Up Arrow' to move the cursor to the top row of the currently selected column (or if multiple columns are selected, to the top row of the left most currently selected columns).
shane