The order in which enumerated values appear in list boxes in the Query and other dialog boxes is the order in which they appear in the Add Field or Modify Field dialog box. This can be a code order or even alphabetic order, but only if they appear in that way in the dialog box. You can use drag-and-drop to rearrange the values.
Many users create a value of <none> to use as the default, to indicate that no value is really being set. They also place this value first in the enumerated list, so that it displays at the top or bottom of the upper pane when the column for the field is sorted. If you are entering a date or time, use the appropriate format for your locale.