I found a very cool way on StackOverflow to calculate age in SQL:
DECLARE @bday date = '6/16/1970'
DECLARE @as_of date = GETDATE()
SELECT [Age] = (0+ FORMAT(@as_of,'yyyyMMdd') - FORMAT(@bday,'yyyyMMdd') ) /10000 --The 0+ part tells SQL to calc the char(8) as numbers
