Trust me, there is no where you are going to go in life where all the people are mature. Being twenty two and working with the general public on a daily basis has taught me that no matter the ethnicity, race, age, or gender of a person is going to help determine how mature they are. I've seen people so old they are nothing but skin and bones and they are the rudest, most foul, and unkempt nasty people there are. Like wise I have met children half my age who show more restraint, understanding, and maturity than I could hope to have within my own self.
If the worse thing you have to deal with is someone saying shit, put on a smile, because at least you aren't having to clean theirs up!