Give me the full name of the first customer, and tell me how long ago he or she wrote his or her first review since making his or her first purchase.
full name = First, Last; how long ago = SUBTRACT(ReviewDate, FirstPurchaseDate);
SELECT T1.First, T1.Last , strftime('%J', ReviewDate) - strftime('%J', FirstPurchaseDate) AS TIMEAGO FROM customers AS T1 INNER JOIN rootbeerreview AS T2 ON T1.CustomerID = T2.CustomerID LIMIT 1