Say what you want it's an opinion, you got yours and I have mine. Hell you can race with a 30LBs. mountain bike if you want. In all seriousness the amount of money you spend in a bike can be earned back with the reliability and longevity. If you start out with 105 you never have to upgrade to race in any of the higher levels, but not the highest. And I doubt you are worried about money then, you're going to want the lightest things you can get your hands on.

But then again I could be wrong. The old saying you get what you pay for. If you are just trying to figure out if you even like cycling, what's the point of asking such a question? If that is the question get a Sora or Tiagra groupset bike.