When they entered the city they went to the upper room where they were staying, Peter and John and James and Andrew, Philip and Thomas, Batholomew and Matthew, James son of Alphaeus, Simon the Zealot, and Judas son of James. All these devoted themselves with one accord to prayer, together with some women, and Mary the mother of Jesus, and his brothers.... (there was a group of about 120 persons in the one place).
We can expect that before His Ascension into Heaven, Our Lady was able to bid farewell to her Son, knowing she would see Him again one day, and that in a mysterious way, He would remain with her and the disciples.
We see her immediately thereafter in the midst of the disciples in the Upper Room. She did not retire on her own, returning to her home in Nazareth to reminisce about her Son. No, rather, she stayed there with His Church, His followers, praying with them, consoling them, being their Mother, as she had been commanded to be.