Adoption question

My husband and I are wanting to adopt, however one big criteria is that a couple has to be married for 3 years. Well we have been married 2 years in September. Does anyone know if that is a grad and fast rule for private adoptions or are there exceptions to certain situations? I'm 36 and when we can adopt I'll be pushing 38 so I'm just wanting to be a mom sooner than later. Thanks for and advice!