Jesus' God is repeatedly described in scripture as the Father. So in John 20:17 it seems obvious that when Jesus said "I to go my God" that he meant that he was going to his father:
Joh 20:17 Jesus said to her, "Do not cling to me, for I have not yet ascended to the Father; but go to my brothers and say to them, 'I am ascending to my Father and your Father, to my God and your God.'"
Would Miriam and the disciples have understood "your God" to refer to the Father? Or to "the Trinity"? (Would there ever be any confusion in their minds as to who was being referred to when Jesus mentioned God?)
In other words, when Jesus said "I go to your God" would they have to stop and think, "Well, my God his right here in front of me"? Or, "I guess he means the other parts of the Trinity"? In other words, did they understand their God to be the same as Jesus' God, or as more complicated than his?