Your coaches didn't say that your forehand was bad because it is a good shot. Kind of like a modern topspin McEnroe forehand. Not much take back, but good enough to beat the best players. The guy you played had a forehand that LOOKED better, but what was the result? Your forehand was superior to his.
If you want to win at your level, it is a great forehand. That's why your coaches liked it. If you want to move up a level, then you should change it and work on it for more power and get some instruction. You have to decide where you want to go.