From the picture it looks healthy, most corals will be lighter colored on growing edges especially if it's growing quickly as the majority of the pigment is derived from the algae in the tissue so new growth that hasn't been established yet will often be white or pale
Its normal, here’s mine after 1 year. Also, it used to be bigger but a few months ago, a Porites rock that was not glued down stumbled a broke a huge chunk of the monti. But yeah, the paler edges are quite common. Just make sure you give it ALOT of flow and keep your tank params (nutrient level, ph level, temperature etc) stable.