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 people (Age INTEGER, People_ID VARCHAR)
TABLE: CREATE TABLE gymnast (Gymnast_ID VARCHAR)

### Question ###
What is the average age of all gymnasts?

### Accurate SQL ###

SELECT AVG(T2.Age) FROM gymnast AS T1 JOIN people AS T2 ON T1.Gymnast_ID = T2.People_ID