The right time to lateral?

BACKGROUND:
I have been at a Credit Rating Agency (Moody's, S&P, Fitch, etc.) for four months. I started straight out of undergrad as an Associate Analyst (comparable to an analyst in IB or associate in ER). I graduated from a small non-target with a 3.9 GPA, Economics and Poli Sci double major, and internship experience at a rating agency, PWM shop and a start-up boutique IB (aka fetching coffee and sending out mail). Also, I played baseball for four years and held the same extracurricular positions that every other person applying for real finance jobs held (president of investing club, participated in blah, etc.).

The finance alumni base at my school is extremely helpful, but the alumni are unfortunately limited to IB, S&T and PWM. I could care less about comp and I prefer not working IB hours, but I want a more challenging position that demands more technical skills than I will find in my current position at the rating agency. For that reason and many many other reasons (ER is just fun...), I want to break into ER and I always have.

QUESTION:
Given that I have been in my current position for only four months, what should be my time frame for making the move into ER? For obvious reasons, I do not want to burn bridges or make a jump too early, but I certainly am dead-set on making the transition at some point. In the meantime, I am reading Aswath Damodaran's book on Valuation and applying it by making my own models to keep myself busy. I plan to do the same with Rosenbaum's. Any other tips to keep myself busy before I deciding to start actively searching for open ER positions?

Thanks WSO!

• "The ceiling is the roof"