How to check if fine-grained auditing (FGA) is enabled in your database

Use the view DBA_AUDIT_POLICIES, which

"describes all fine-grained auditing policies in the database. Its columns are the same as those in ALL_AUDIT_POLICIES."

SELECT  POLICY_NAME,ENABLED,AUDIT_TRAIL
FROM  DBA_AUDIT_POLICIES;

Result:

POLICY_NAME	ENABLED	AUDIT_TRAIL
MY_FGAPOLICY_1	YES	DB+EXTENDED
MY_FGAPOLICY_2	YES	DB+EXTENDED
MY_FGAPOLICY_3	YES	DB+EXTENDED
MY_FGAPOLICY_4	YES	DB+EXTENDED

Documentation of the ALL_AUDIT_POLICIES can be found here