In a county designated pursuant to section 19-1-123, if a child is under six years of age at the time a petition is filed in accordance with section 19-3-501 (2), the child shall be placed in a permanent home no later than twelve months after the original placement out of the home unless the court determines that a placement in a permanent home is not in the best interests of the child at that time. In determining whether such a placement delay is in the best interests of the child, the court must be shown clear and convincing evidence that reasonable efforts, as defined in section 19-1-103 (89), were made to find the child an appropriate permanent home and such a home is not currently available or that the child's mental or physical needs or conditions deem it improbable that such child would have a successful permanent placement. The caseworker and the child's guardian ad litem shall provide the court with a report specifying which services are being given the child in order to remedy the child's problems. The case shall be reviewed at least every six months until the child is permanently placed. The six-month reviews and twelve-month permanency hearings shall continue as long as the child remains in foster care. Clear and convincing standards of evidence shall be applicable at any such review. For the purposes of this section, a permanent home shall include, but not be limited to, the child's reunification with the child's parents; placement with a relative, with a potential adoptive parent, or permanent custody granted to another; or, if the child cannot be returned home, placement in the least restrictive level of care.