I graduated in May, 2006 with a BS in ME and did not take the FE until October, 2008. I think the only advantages to taking it right at graduation would be 1) of course the material is fresher on your mind and, more importantly, 2) you are probably still in a test-taking frame of mind.
By waiting 2 and a half years, I probably had to struggle a bit more to revive my testing skills. I did this by enrolling in an FE course at the local college, which served more to keep me on a consistent study schedule than to provide educational material.
Probably the greatest advantage of having 2 years in the field before taking the test was that I could apply a lot of the exam material to my daily work. Not to mention, being a Project Manager, I now know the value of creating personal deadlines and keeping myself on track. In college, I was much more fly-by-the-seat. Cramming 12 or 16 hours the night before a test was commonplace. Of course, then it was also commonplace to find B’s and C’s on my final grades. By implementing a strict schedule to study for the FE, I easily scored in the top 10 percentile, which I don’t think I would have ever done if I had taken the exam immediately after graduation.
Everybody is different, though. You sound like you are much more responsible in college than I was. Some people just take a little longer to grow up, but I’m finally an EIT and plan to get my PE in 3 years when I’m 30 – better late than never. Good luck.