How to use ST_Transform when inserting new row?

I have written a script which reads a CSV file with lat/lon coordinates in WGS84 and inserts them into a table in PostGIS. What I want to do now is to change the insert query in order to make a transformation of the coordinates from WGS84 to another reference system. My qyestion is if something like this is possible while inserting the data.

I was trying something like this but doesn't work:

   INSERT INTO imgRural(geom) VALUES (ST_Transform(ST_GeomFromText('POINT(23.771111111111 38.013888888889)', 2100)),2100) RETURNING imgId;

What am I missing here? Thanks.