Pope Benedict XIV (1675-1758 AD) explicitly banned women and girls from serving the priest during the Mass, and appealed to two other Popes - Pope Gelasius II (1060-1119 AD) and Pope Innocent IV (1195-1254 AD) - who had done the same:
Pope Benedict XIV - Allatae Sunt (1755 AD)
29 Women Assisting at Mass
Pope Gelasius in his ninth letter (chap. 26) to the bishops of Lucania condemned the evil practice which had been introduced of women serving the priest at the celebration of Mass. Since this abuse had spread to the Greeks, Innocent IV strictly forbade it in his letter to the bishop of Tusculum: “Women should not dare to serve at the altar; they should be altogether refused this ministry.” We too have forbidden this practice in the same words in Our oft-repeated constitution Etsi Pastoralis, sect. 6, no. 21.
Notice that the above uses moral language. Women serving in the Mass is called an "evil practice", and an "abuse". Consequently, it is "strictly forbidden", on those grounds, and on the grounds of tradition (two other Popes).
The Code of Canon Law used to reflect this prohibition, in stating that lay "men" are to be considered eligible for the ministry of altar server:
1983 Code of Canon Law - Canon 230
§1 Lay men whose age and talents meet the requirements prescribed by decree of the Episcopal Conference, can be given the stable ministry of lector and of acolyte, through the prescribed liturgical rite. This conferral of ministry does not, however, give them a right to sustenance or remuneration from the Church.
However, in 2021, Pope Francis issued a Motu Proprio letter in which he officially amended the Code of Canon Law to allow women and girls to be altar servers:
Pope Francis - Spiritus Domini (2021 AD)
Accepting these recommendations, a doctrinal development has taken place in recent years which has highlighted how certain ministries instituted by the Church are based on the common condition of being baptized and the royal priesthood received in the Sacrament of Baptism; they are essentially distinct from the ordained ministry received in the Sacrament of Orders. A consolidated practice in the Latin Church has also confirmed, in fact, that these lay ministries, since they are based on the Sacrament of Baptism, may be entrusted to all suitable faithful, whether male or female, in accordance with what is already implicitly provided for by Canon 230 § 2.
Consequently, after having heard the opinion of the competent Dicasteries, I have decided to modify canon 230 § 1 of the Code of Canon Law. I therefore decree that Canon 230 § 1 of the Code of Canon Law shall in future have the following formulation:
“Lay persons who possess the age and qualifications established by decree of the conference of bishops can be admitted on a stable basis through the prescribed liturgical rite to the ministries of lector and acolyte. Nevertheless, the conferral of these ministries does not grant them the right to obtain support or remuneration from the Church”.
Notice the cure-all of "doctrinal development" is used to excuse what is just another irreconcilable contradiction in the doctrine of two "Vicars of Christ". This will never be anything more than a dishonest excuse to pretend that contradictions and revisions in doctrine don't actually present the problem that they manifestly present to anyone who is concerned about the truth.
This change reflected what had already become commonplace in the Catholic Church when I was still a Roman Catholic. I was an altar server with girls prior to 2014 in middle school. Yet, according to tradition, three Popes expressly condemned such an "evil practice", which was an "abuse".
Cardinal John Henry Newman famously said "To be deep in history is to cease to be Protestant". In reality, for those with eyes still open to see the truth, to be deep in history is to find that the Roman Catholic Church is a manifestly false branch of Christianity, which has a mass of self-contradictory doctrine taught by those that it declares to be infallible.