I am a 24 years old guy and have been working in Software Industry for the past 2 years.
I don't know what other details to put in this question! but, is it parent's obligation to pay for my marriage? What does Islam says?
I think once you are mature and could earn for your living you are responsible. And paying for your marriage is a way to show you are able to be in charge for your wife and family. And your parents can assist you and even more.
Note that some madhabs consider the fact that a husband is able to be in charge for his wife (and family) as a very important condition for the marriage to stay strong. And consider the opposite as a possibility for the wife to ask for divorce (See my answer here)!
As there's no rule in Islam AFAIK saying parents must do so until a certain age. They are not asked to pay for your marriage. Therefore it wouldn't be their duty by shari'a. But they still are free to do so,as it is their son and they might want to help him and want him to be happy etc..
Anything else would be a culture related matter and not directly related to Islam.