"... I said no, I am not going to let you in the outlaws at all." Jason repeats himself with no place for further argument. Of course, he's not going to let you get in his team. First, you are young- no actually scratch that, first you are his younger sibling and second, you don't have the heart to do what him and his team does, so it's a big no for Jason. The reason why he told Dick to let you in his Teen Titans small team, was because it was safer for you in the first place.