I don’t know too much about IMC, but if your goal is to get the CFA charter (and not really the IMC), then it may make more sense to get started early for June 2015. You can probably easily put 400 hours and have an unstressed, strong Level 1 performance.
IMC is comprised of less than Level 1 CFA as far as I know. Might be a good warm up if you’re looking at CFA Level 1 in June 2015, but if you’re definitely going for CFA then I’m not sure if IMC will be as helpful.