user: Question: How old was the mother who delivered on December 15, 2008?
Columns: ['Congresswoman', 'State', 'Date of delivery', "Mother's age", 'Baby gender']
Types: ['text', 'text', 'text', 'real', 'text']
Sample row: ['Yvonne Braithwaite Burke', 'California', 'November 1973', 40.0, 'Girl']
SQL:

assistant: SELECT "Mother's age" FROM "Table" WHERE "Date of delivery" = 'December 15, 2008';