If you need to know a great deal about this, you need to be a great deal of research on it. Start with the Colorado State Code.
Colorado does require a permit carry a concealed weapon. It also permits open carry in MOST places.
Colorado does limit possession of firearms by minors, but makes exceptions, such as when minor has written permission of parents, is on property owned by parents, etc.
I am not a lawyer, and you should be very careful about legal advice on the internet. Go directly to the state laws, and read what they say.