H.M.
Colors,letters,numbers/counting
This is the most common order that I see. I am an assistant director at a preschool. But remember each child is different. It also depends on what you spend the most time showing and teaching them. Most of us read a lot and so they will see colors and letters a long before they see numbers. Remember. Even if your child is 5 mos. old if you are reading a book about colors they are soaking that in! The letters and the colors! If you read more books about counting then they may pick up on that first! The important thing is that the child is exposed to reading books!
H.