what has been the first time a medication was prescribed for patient 63676 since 04/2104?
select prescriptions.startdate from prescriptions where prescriptions.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 63676 ) and strftime('%y-%m',prescriptions.startdate) >= '2104-04' order by prescriptions.startdate asc limit 1