I did the same thing in SW Georgia and my garlic is 12″ tall.  Everything I have read is that it will go dormant until it is ready for harvest in the summer/fall.   Also a new student and completing my assignment  🙂

I’m in central Tennessee and have grown garlic for many years. Each year I plant it in October, and expect it to get about 6 inches tall at least by the new year. Then it just sits happily over the winter until it takes off in spring. I think the goal of planting it in fall is that it will grow a little and get leaves up. Then it can do photosynthesis and build a root system over the winter. Come spring it is ready to take off. So it sounds to me that both of you should expect a garlic crop. It might be ideal if they hadn’t grown quite so much before winter set int, but I do believe you will still get a harvest. The cold temperatures should be just fine on the garlic leaves as they are very cold hardy.

I am in Michigan. I plant my Ukranian rose garlic every September/October and it sprouts up some even with leaf mulch on top. It has been covered in a foot of snow and now with the snow melted it’s still standing and doing fine. I have never had an issue of it getting damaged because it sprouted too early here in the great white North.