Hi there! I"m fairly new at this myself, so I'm just able to tell you what I've learned so far. Depending on where you live in CO, you may have a charter school that has a homeschool option where you enroll part-time. The two in the area I'm familiar have you purchase the curriculum for the class, and they meet 1-2X a week. The other option in my area is fairly new, but it looks like you kinda pick and choose and develop a plan with an instructor at the school. You do have the option of COVA (Colorado Virtual Academy). It is a charter school through Adams County District Five Star Schools that you do at home. They use the k12 curriculum, and it is free (public school at home), along with the materials (aside from things like paper and ink).
Colorado, I think, is relaxed when it comes to homeschooling. You simply fill out an intent to homeschool form with your local district. Compulsory attendance age is 7. And you're suppose to average 4 hours/day. Also, you have to follow the state testing schedule and test at a local school or privately.
Hope this is some help to you and that you can make sense of what I typed out! I have tired pregnant mama brain today.