workout consistantly

I currently weigh about 160lbs. at 5ft. 11inch. that’s not great. I want to play pro hockey and I may even be good enough, I just don’t have the size. At my height I should weigh more like 180 or 190. I have recently started working out everynight. I want to continue until I am at the weight I want to be at and then I want to continue to keep that weight. I have gone to the gym before, but eventually I miss a day and the a few days later another and another then I stop going. I want to keep going and get my size and keep it this time. My future as a pro hockey player may depend on this.