Fudgecakes,
Actually I am having the same situation as you, deciding which of these 2 lens to buy as I am holding a DX cam.
For me, I have decide to get 24-70mm as I know what I am using it to shoot for and may have the decision to upgrade to FX cam in future without again need to sell away DX lens to get FX lens. No doubt I will sacrifice the wide angle focal length but there is no perfection for having a fast lens but without the need of changing the lens for wide angle. Unless you opt for the kit lens like 18-105mm or 18-200mm.
You mention that you will be taking alot of CCA events, maybe some portrait shots. I think wide-angle focal length is not your main consideration now. I can see that you are still young and studying. If your passion of photography is still strong, who know you may upgrade to FX cam in future when you are the spending power. By then 24-70mm has become a great investment asset to you.
Hope this helps you on making a decision as I just made mine. :bsmilie: