If you crocheted a bag using knitting wool and not wool roving, it may not felt it at all! It all depends on the type of wool which you used to crochet the bag. If it is pure wool, it will felt but is unlikely to if the wool is synthetic or if the synthetic content is too high. If I am wet felting with wool roving, I start off with the template still being inside the project during the early stages and remove it when the wool begins to felt properly. Always keep a careful check on the contents of the dryer to avoid shrinking the project too much. I would insert a piece of floor laminate underlay, bubble wrap or even cardboard inside the project to be on the safe side.