I always transit C to A because my city is XE only. The lowest amount of time ive done it in was with a 37 minute connection and i barely made it. You were smart to make the switch in flights.

As for your question, I really don't know. Most airlines use 30-35 mins as a MCT but in EWR, it can be a problem. I have had 45 and 57 min connections and have been fine but that is because the wind wasn't blowing the wrong direction.