Keg Bomb

I think this is extreme anxiety talking, but I have a question about maximum keg pressure.

I brewed my first extract batch in a long while. It is a brown ale that started at 1.051 or so and I used US-04. I had it in a primary for 13 days then moved it to a secondary for seven days (I needed the primary). When I kegged it, it was at 1.016. I primed with 1/3 cup of cane sugar. Now, 1.016 seems high to me as it is 69% apparent attenuation. What is the worst that could happen if it wasn't finished? Would the pressure relief valve kick in? Is it even possible that it could now hit 130 psi? Am I just crazy? I realize that ideally I should have taken a few reading, but that is past. Thoughts?

1.016 is not too high, definitely not enough to give you enough pressure to trigger the pressure relief valve... which is what would happen if you ever got to around 130 psi. It'll be just fine.

I'm sure you're fine. Hypothetically, if you filled the entire keg full and there was no room for gases to fill in, you might have a problem. You can always pull the pressure relief valve for a second if it makes you more comfortable though.