I think that a messenger bag is probably okay, but carrying it properly could be a problem. Just don't wear it over your shoulder with the strap running across your chest over to the other side and in combination with an open collar dress shirt showing white undershirt at the neck. Seems to be the style in NY for IT people but to me in the financial world it looks very geeky. It would not fit in the legal world either, IMO. John
I take the 6th! Not only is a messenger bag age appropriate, it is the trendy choice as well! Good luck!