When to begin informational interviews for summer analyst internships?

Hi WallStreetOasis,

I'm currently a freshman at a target that's trying to mentally layout my career plans for 2014. My goal is to get a middle market investment banking summer analyst internship for the summer of 2015. I understand that getting informational interviews is really important to the recruiting process. What's the best time to start contacting alumni for an informational interview? I'm thinking of early September right now with the logic that any earlier they'll begin to forget about me and any latter it will become harder to build rapport. I'd appreciate any feedback on my current game plan.