Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE volume (Weeks_on_Top INTEGER, Artist_ID VARCHAR)
TABLE: CREATE TABLE artist (Artist_ID VARCHAR, age VARCHAR)

### Question ###
What is the average weeks on top of volumes associated with the artist aged 25 or younger?

### Accurate SQL ###

SELECT AVG(T2.Weeks_on_Top) FROM artist AS T1 JOIN volume AS T2 ON T1.Artist_ID = T2.Artist_ID WHERE T1.age <= 25