Do I have to file for divorce where my children were born in?

Since you have been in LA with the children for more than the past six months all issues concerning custody and parenting of the children must be done in Louisiana regardless of where the divorce case occurs. Where they were born is irrelevant. If you and your spouse lived together in Colorado before you left and he has remained there, you have a choice of pursuing the divorce either in Colo or in LA. You should consult an attorney to learn more about the pros & cons of where to file and to discuss your options based on your principle objectives.