Can you check in at 12 pm?

3 pm...normally

I would definitely call them. Whenever I want to check in early at a hotel, I always call before I arrive.

You can, you just need to ask them and see if they have a room ready. I checked in about 1:15.

All check in times are 3p.m

no unless pre arranged if not then it's 3pm as they need to clean rooms