It is interesting that even in aikido we must be cognizant of the fact that we constantly form paradigms, stereotypes, and prejudices against people. I think one of the biggest goals of aikido is to simply accept what is presented in a situation for simply what it is...without all the distractions. i.e. you are a person...period.
The good news is that you are in a wonderful art that should at your young age teach you how to better deal with these things. In some cases it may become more apparent in the dojo since we are creating conditions of conflict that isolate many, many feelings, emotions, and prejudices!
Your training, as my wife has found, helps here confront the realities that exist in the workplace and the world.
My advice is to try and embrace those moments, work with them to better understand yourself and how you are going to react/proact, or respond to such situations in the future.
Remember first you must influence yourself before you can influence others!
Good luck in your training!