Unfortunately its no mater of time... In most cases is a matter of creating good content and sometimes luck. It's possible to be given merit for your first post if it's really valuable, important, interesting sometimes funny etc.
You wrote, that you have been posting good posts... I've scrolled down your history - it wasn't hard work because your started to make real posts one week ago after hard bounty report training... 

So which of them deserve merit in your opinion? link it and write shortly why?