Whether you as an adult can be adopted depends on the law of the place where the adoption takes place.
Even if you can be legally adopted, the adoption would not be of any use to you for immigration purposes as under immigration laws, among other requirements, the adoption must have occurred before the age of 16 for you.
Godmother is not a statutory relationship entitling immigration benefits.
There may be other ways to accomplish your goals. You may want to review your facts and options with an attorney.