monpetitchoux,
You are both correct.
With approximately 200 cultivars of "bell peppers", there is a great variety of colors which come from ripening.
Most turn colors which can be any of the following: red, yellow, purple, brown, golden, or orange when the peppers are allowed to ripen on the plant.
A cultivar called ""Permagreen" stays green. They can be found at a place called "Sand Hill Preservation Center" in Calamus, IA.