(c) If the minor admits the allegations of the petition, the children's court shall proceed to the dispositional stage only if the children's court finds that:
- (1) The minor fully understands his or her rights as set forth in § 11.906 of this part and fully understands the potential consequences of admitting the allegations;
- (2) The minor voluntarily, intelligently and knowingly admits to all facts necessary to constitute a basis for children's court action; and
- (3) The minor has not, in the purported admission to the allegations, set forth facts which, if found to be true, constitute a defense to the allegations.