I think my 13-y/o niece needs makeup consultation...?

its free at most beauty counters! if you would like to help her, see what celebrities she admires (at her age id guess miley cyrus) and suggest that she wear less make up like she does. but in all honesty, short of this theres not much you can do, shes at a tempermental age and saying you have noticed these things will scare her a little, and your're right she needs to make mistakes! But she is loucky to have such a helpful uncle aha :)