The sacramental register would list the sponsor. You can inquire at the parish office.
A parent cannot be the sponsor of their own child. The other two would have been canonically able to be sponsors, in fact it is preferred to have a baptismal sponsor also be a confirmation sponsor.
Can.* 892 Insofar as possible, there is to be a sponsor for the person to be confirmed; the sponsor is to take care that the confirmed person behaves as a true witness of Christ and faithfully fulfills the obligations inherent in this sacrament.
Can.* 893 §1. To perform the function of sponsor, a person must fulfill the conditions mentioned in ⇒ can. 874.
§2. It is desirable to choose as sponsor the one who undertook the same function in baptism.
Then you did not have a sponsor. And, no, that would not impact your confirmation in any way (see above).
For baptism you may have one or two, if two they are to be one of each sex. For confirmation,there is one sponsor.
Can.* 872 Insofar as possible, a person to be baptized is to be given a sponsor who assists an adult in Christian initiation or together with the parents presents an infant for baptism. A sponsor also helps the baptized person to lead a Christian life in keeping with baptism and to fulfill faithfully the obligations inherent in it.
Can.* 873 There is to be only one male sponsor or one female sponsor or one of each.
Can.* 874 §1. To be permitted to take on the function of sponsor a person must:
1/ be designated by the one to be baptized, by the parents or the person who takes their place, or in their absence by the pastor or minister and have the aptitude and intention of fulfilling this function;
2/ have completed the sixteenth year of age, unless the diocesan bishop has established another age, or the pastor or minister has granted an exception for a just cause;
3/ be a Catholic who has been confirmed and has already received the most holy sacrament of the Eucharist and who leads a life of faith in keeping with the function to be taken on;
4/ not be bound by any canonical penalty legitimately imposed or declared;
5/ not be the father or mother of the one to be baptized.
§2. A baptized person who belongs to a non-Catholic ecclesial community is not to participate except together with a Catholic sponsor and then only as a witness of the baptism.
Then you don’t. It has no impact on the validity of the sacrament of baptism or confirmation.
A Catholic can be a sponsor to as many children or adults as they please.