@thepro8, you definitely need to be doing some winter watering with the mild weather Colorado has been having. Here's a great (and short) CSU extension article on the topic.
I'd hate to see you get fooled by the surprise highs and lows Colorado weather might throw us over the next 60 days. Historically, the last freeze can happen as late as Mother's Day.
If your system can be drained quickly (and you know how to do so), feel free to start it up. If not, you might have a $50-$100 service call for a spring sprinkler blowout the first week of May