I can offer only a single data point, but your experience mirrored my second batch almost exactly. It was a regular Keystone Cops exercise in incompetence. I was overzealous when pre-warming my mash tun and ended up with my mash at 166. Panicking, I stuck my chiller in and managed to get it to about 140 faster than you can drop a carboy on a concrete patio. I then added very hot water to get it up to the mid 150s, where I made my first smart decision of the day and quite effing with it. This was on March 16.
I'm down to my last 4 bottles of it, and sorry to see it go. It came out great, and me and my friends have enjoyed it. The process is surprisingly tolerant of beginners mistakes.
I bet you'll be just fine. But please let us know-- this is how people learn.