It is a certain teaching of our Faith that each of us has a Guardian Angel
"Every one of the faithful has his own special guardian angel from baptism. (Sent. certa.)" (Ott, L. (1957). FCD. 120–121)
Furthermore, "According to the general teaching of the theologians, however, not only every baptized person, but every human being, including unbelievers, has his own special guardian angel from his birth. This view is biblically founded on the words of Our Lord. Mt. 18:10" (ibid)
Mt 18:10 - "See that you despise not one of these little ones: for I say to you, that their angels in heaven always see the face of my Father who is in heaven."
A look at the Early Church Father's understanding of Mt 18:10 further reveals the Church's teaching
“Therefore are they not to be despised for that they are so dear to God, that Angels are deputed to be their guardians” (St. Anselm)(Catena Aurea, Thomas Aquinas, S., & Newman, J. H. (1841).
“I esteem it, O my God, an inestimable benefit, that thou hast granted me an angel to guide me from the moment of my birth, to my death.” (St Augustine, De dilig. Deo. Medit. c. xii)( Haydock, G. L. (1859). Haydock's Catholic Bible Commentary)