Is it ok to be racist to only the TEENAGERS of that specific race?

Im 17. Male. White. I honestly dont like mexican american teenagers. They are very Rude, mean, and arrogant to other races. Especially the girls who think they look better than everyone else. Wtf is this about? The the adults however age range from 21 and up are cool. Except the fact that some are a little racist. What for though? Who knows? Anyway...most of the adults are nice people based on what i have seen. I heard the mexican american teenagers didnt used to be like that. And what really irks me the most is that they all consider themselves Mexican as if they were born there. I love black people. Kind, funny, cool, and just normal. Although there are some rude ones (like every other normal race). But mexican americans are just off the charts. Is it ok to be racist to mexican american teenagers or am i just plain racist