Re: New User needing help with her kitten please!!!
Welcome, and I agree. This place is new to her and it hasn't registered to her that this is now 'home'. Her pawing at the door handle is showing you how smart she is, because she knows that is the key to opening the door. All she knows right now...is she wants to go out that door and try to find her 'home'. I know it is sad to think of her being confused about this, but it will just take some time for her to learn that this place, is now 'home'.
Extra cuddle-times, more playing sessions and whatever else you can think of to help her settle in and feel more comfortable. Please do not think you are being cruel. Many cats live perfectly good and healthy, enriched lives indoors. If you are in the 3rd story, this would make it very difficult for her to be an indoor/outdoor kitty. I live rurally in America and I still keep most of my cats indoors. I do have a few 'barn cats', but they moved into my barn as ferals already aware of the dangers outdoors and are able to manage themselves just fine. Most of my indoor cats I would be afraid to let them out because they just don't have the skills/knowledge to survive safely outdoors without supervision or containment.
Just give your Millie time and reassurance, she will eventually adjust.