I wish there was a way to discount the first month of reviews from the overall score. I assume that the people who buy, play, and review the game immediately are the super fans who have extreme views on what makes the game good.

There is! You can click and drag on the review date graph to any custom timeframe you want. Then it'll calculate the overall rating of just your selected date range for you.

I wish I could post an image here for you :( But basically just go down to the reviews, expand the graphs (with "Show Graphs"), and click and drag a box on the left hand one.