The dependency court did not abuse its discretion by finding a moderately mentally retarded witness competent to testify based on her answers to the court’s questions. Following an allegation of sexual abuse of father’s girlfriend’s daughter, Kimberly, a petition was filed alleging that father’s children were also at risk of sexual abuse. Prior to the jurisdiction hearing, DCFS reports were admitted into evidence showing that Kimberly was a special education student with a diagnosis of moderate mental retardation. Father did not object to Kimberly’s testimony on competence grounds. The juvenile court found her competent as a witness, and sustained the petition. On appeal, father argued that the finding was based on incompetent evidence. The appellate court affirmed the judgment except as to a 19-year-old sibling who lived in another home. Father waived his claim by failing to object. Nor was it ineffective assistance of counsel to fail to object to the testimony, because the objection would have been overruled. Even if he had not waived his claim of error because of forfeiture, the court properly questioned Kimberly and determined that she was qualified. It was not an abuse of discretion to find her competent to testify.