Krav Maga/Bjj/Muay Thai

I have been toying with the idea of doing Krav maga on a Mon and then Bjj/M Thai on a Friday. I have done Krav before and enjoyed it. I have tried Bjj before but my lack of a background in this type of martial art left me thinking I have years ahead of me before I become any way proficient. Being an impatient type of character I can envisage months of frustration though I would love the sense of achievement that comes with attaining a belt in the Bjj. I'm 36, is it worth it?

Thanks