I can appreciate your desire to baptize your mother, but Canon Law allows adult baptism only under the following circumstances:
Can. 865 §1. For an adult to be baptized, the person must have manifested the intention to receive baptism, have been instructed sufficiently about the truths of the faith and Christian obligations, and have been tested in the Christian life through the catechumenate. The adult is also to be urged to have sorrow for personal sins.
§2. An adult in danger of death can be baptized if, having some knowledge of the principal truths of the faith, the person has manifested in any way at all the intention to receive baptism and promises to observe the commandments of the Christian religion.
Catechism of the Catholic Church:
1256 The ordinary ministers of Baptism are the bishop and priest and, in the Latin Church, also the deacon. In case of necessity, anyone, even a nonbaptized person, with the required intention, can baptize, by using the Trinitarian baptismal formula. The intention required is to will to do what the church does when she baptizes. The Church finds the reason for this possibility in the universal saving will of God and the necessity of Baptism for salvation.
1278 The essential rite of Baptism consists in immersing the candidate in water or pouring water on his head, while pronouncing the invocation of the Most Holy Trinity: the Father, the Son, and the Holy Spirit.
Don’t let worry and/or discouragement take root in your heart (John 10:10). Your prayers and sacrifices offered in faith for your mother are efficacious. For, “If our prayer is resolutely united with that of Jesus, in trust and boldness as children, we obtain all that we ask in his name, even more than any particular thing: the Holy Spirit himself, who contains all gifts” (Catechism 2741). Remember, God loves your mother more than you can ever love her. He also wants her to live forever in heaven with him (2 Peter 3:9)! I will pray for you both.