I am having the same problem I had last year my pepper plants are 7" tall and they are making marble size peppers. The plant nursery must start these from seeds in January.
Last summer I bought a bell pepper from the grocery store and planted all the seeds in a circle around the pepper plants that I bought. The seeds grew and I thinned out the plants and they out grew the store bought plants and made some good bell peppers.
I sweet banana peppers have peppers 1" long that are ready to pick.
I think I will plant some seeds tomorrow.