Everest

This is most likely an extremely stupid question, but i just dont want to make an a** of myself. I am going to begin racing this season and will be riding unattached without a club. I am wondering what I should wear for a jersey I have a number of pro team kits and quite few jersey's from local rides, however I am assumeing I should probably wear something plain. Should I go buy a cheap plain jersey from Performance or Nashbar? or does it matter and I can wear pretty much whatever? Am I totally over thinking this? Whats normal for unattached riders?