I have Reverse Imposter Syndrome, help!

No matter who I meet, I just assume I'm more of an expert than they are. I challenged my civ pro professor on Iqbal and he's a district court judge. I challenged my con law professor on Hamdan and he's represented prisoners at Guantanamo.

I'm only slightly above median gpa at a school some would consider tier 2 while others wouldn't consider at all. I am not on my school's journal. I have only clerked at a mid-sized firm. I go part-time. I'm in my thirties. And I don't know what a Cali award is, let alone have I been given one.

Yet, I'm confident I know the law better than anyone. I even regularly prove it, by having the longest discussion posts and speaking the most authoritatively in class about moral issues.

Please help. What can I do? Does everyone feel this way at some point? When does it go away?