Bunt is laid down....who covers third in this instance?

[bombdiggity]

Hello all, I'm new, from Australia and have a question.

We had a play on the weekend where a bunt was laid down with a runner on first (I play first base) and I was the only one who had anticipated it. I went to field the ball which started to roll up third as the pitcher was standing like a shag on a rock and third base was way back near the bag. The catcher stayed where she was. Third base finally moved and fielded the ball. As third didn't have a player covering it, I continued around to third base to provide cover there so that the runner who had rounded second wouldn't advance. I had been taught this by another coach (who encouraged thinking outside the square). At practice an older player (who has never played at a high level) berated me for doing what I did and said that the catcher should've covered third....I stated that she was still standing behind the plate and had no chance of making third before the runner got there.

I'd like some thoughts on this please!