I was a sponsor for one of my peers in RCIA this year; he received Baptism, Confirmation, and Eucharist. Am I his godfather?
you are his godfather if you stood with him at baptism. A sponsor might be the person who accompanies a catechumen up to the rite of election. Godparent takes over at the rite of election. Sometimes the same person is both sponsor and godparent. Sponsors are often assigned but the those being baptized get to pick their godparent, and often chose the same person who has accompanied them from the beginning.