If they are growing well, this often delays fruiting and they will eventually settle down to berrying. They should do so by four or five years but if the ground is rich or you feed a lot and they grow quickly they may not set berries. Also the older established may be males.
You can easily check for males or female flowers, but looking at the open flower. The males have 4 pollen-carrying anthers and the females do not, but have a small round berry at the cetnre of the flower.