Peach trees normally flower and fruit within a few years after planting, but it's not unheard of for a 7-year-old tree to not yet fruit. Several factors could be involved. Fruit buds are more tender than vegetative buds, so your tree may have formed fruit buds that have been killed off over winter. This is especially true if you've had severe late winter cold.
If the tree is growing extremely well, it may be getting excess nitrogen fertilizer, which promotes vegetative growth, but deters fruiting and flowering.