Excel Keyboard Navigation question

I am looking for the keyboard shortcut for the following scenario: I begin typing in a cell and Excel auto-completes the entry while highlighting the entry and place the active cursor within the cell at the end of the selection. The auto-completion is not always correct, so I'd like to use the keyboard (not the mouse) to move the cursor to the beginning of the selection to begin typing. I can highlight/un-highlight by using "Shift"+"Arrow Left/Right", but this doesn't move where the cursor is within the cell, so when I start typing the entry begins at the wrong location. I would like to un-highlight and move the cursor. Please note: this post is about navigation within a cell.

Is there a keyboard shortcut to accomplish this?

Thanks so much.