For some reason Google has decided I'm under 18 (despite being verified as an adult on YouTube!) and has disabled a number of services incl. Ad Personalization, Location History, forced me in to using SafeSearch, among others. Seems like a few people on Twitter have had this happen to them as well, and it won't let you reverify if you've already told them you're over 18. Even in my Ad Profile it says "18-24 years old"!