I don't see anything in the Adsense guidelines that saysI don't see anything in the Adsense guidelines that says the age a site has been active is a factor for when it can sign up for Adsense. So the answer would be zero months. You can sign up immediately.
Based on the age a site has been active is a factor for whenlink you provided in your content it can sign up for Adsenseappears you do have to wait six months due to be located in India. SoGoogle isn't clear on whether the answer would be zerosix months is from the registration of the domain for the launch of the site. You can sign up immediatelyshould submit your site for inclusion at the six month anniversary of the registration date and if you are rejected try again at the six month anniversary date of the site launch.