What age does categorize a person to be mature enough to Gamble?
I would go with 18 but only if the person has income already. Without which, he/she better not play with money. I may sound too conservative but the economic reality from which I am speaking tells me that a person better spend the money he/she didn't earn elsewhere rather than burn it on gambling as if it was just picked up from the streets. Money is hard to find in this part of the globe!
Does the age even hold a meaning? Should it be regulated?
Yes to both! More often than not, with age comes sense of responsibility and maturity.
This should be the main reason why kids are not allowed to gamble simply because they are not mature yet and they don't know the risk of doing it. A guidance from the parents plays an important role on this matter, we have a good culture about this thing where the parents are so strict even up to the age of 18, I just don't know the culture of other countries.