I believe he knew.....................the reason being is because it was the mother of Moses that was his nurse maid and they usually nursed a child from 3 to 7 years......note the bolded....
Exodus 2:1-8: Now a man of the house of Levi married a Levite woman, and she became pregnant and gave birth to a son. When she saw that he was a fine child, she hid him for three months. But when she could hide him o longer, she got a papyrus basket for him and coated it with tar and pitch. Then she placed the child in it and put it among the reeds along the bank of the Nile. His sister stood at a distance to see what would happen to him. Then Pharaoh’s daughter went down to the Nile to bathe, and her attendants were walking along the river bank. She saw the basket among the reeds and sent her slave girl to get it. She opened it and saw the baby. He was crying, and she felt sorry for him. “This is one of the Hebrew babies,” she said. Then his sister asked Pharaoh’s daughter, “Shall I go and get one of the Hebrew women to nurse the baby for you?” “Yes, go,” she answered. And the girl went and got the baby’s mother. Pharaoh’s daughter said to her, “Take this baby and nurse him for me, and I will pay you.” So the woman took and the baby and nursed him. When the child grew older, she took him to Pharaoh’s daughter and he became her son. She named him Moses, saying, “I drew him out of the water.”