you are free to apply to be a merit source if you believe your local need an active merit source. theymos may consider including you as merit source based on your judgement of sharing merits.
I don't know about that cause a year ago my fellow legendary countryman applying for merit source but sad to say didn't accepted. And I don't know also about this if low ranks applying for Merit Source got accepted. Anyways that's not the problems here we can Post in global section and get merit.
There is no rank criteria to become merit source and the merit sources information isn't publicaly available so we also can't say that newbies can't be a merit source but the criteria from theymos is very clear collect 10 worthy post which deserve merits and you should be a recognised member in the community.