what is the oldest age a person can be adopted
Report Abuse. In many states, you can adopt the child of a family member and the child of your best friend at 18. Otherwise, it is 21. Yes, I know some of you will wonder about the child of a best friend.It is completely at the judge's discretion and many will allow it unless that best friend is otherwise unfit.In this case, however, the mother has indicated her preference for her friend to adopt the child-it's not just out of the blue.es, I know some of you will wonder about the child of a best friend. It is completely at the judge's discretion and many will allow it unless that best friend is otherwise unfit. In this case, however, the mother has indicated her preference for her friend to adopt the child-it's not just out of the blue.