given an id number calculate age in mysql

1SELECT * FROM (	SELECT		borrower_idcard idcard,		substring(borrower_idcard,7,8) birth,		year(now())- year(substring(borrower_idcard,7,8)) age,		borrower_name NAME	FROM		jr_finance_business_info	WHERE		loan_time >= 1483200000	AND loan_time < 1514736000	and `status`>=0	and xu_business_id = 0	and borrower_idcard  != '' ) t1 where t1.age>=18 and t1.age<=24;