Question: When Andrew returns to Little Miss in 2068, he is shocked to see Portia. Why didn't Little Miss ever tell Andrew about Portia while Andrew was away? They kept in contact with each other.
Question: What year do you think it is when Andrew returns to the Martin family home and meets Portia, as well as the older Little Miss?
Answer: According to various wikis, the year is 2068.
Question: Why does Miss (Grace) hate Andrew so much?
Answer: She's a smart ass, know-it-all. A delinquent who never grew. I have a sister who is the exact same way.
Question: Andrew was obviously 200 years old when he died. How old do you suppose Portia was when she passed away?
Answer: Between 125 to 150 years old, her life was extended by the artificial body parts developed by Rupert Burns. Andrew traveled the world for nearly 20 years before returning home, at which point Portia was about 25 years old.
Answer: It's been 20 years; everyone loses contact. Little Miss didn't know where Andrew was or how to contact him. He was constantly on the move. He contacted her, never saying specifically where he was or how long he would stay there.