Yes, this behaviour is often considered rude however, it doesn't sound like you meant it to be. I don't know if it's the same for you but I will always try to get a good look at T during sessions so that I can hold onto that picture of her between sessions. I don't look her up and down but will look at different things at different times like when we talk I will obviously look at her face, when things fall silent I will maybe look at the floor/her feet, when she greets me at the door I get a full view of her, stuff like that. If you can, I'd suggest talking about this with her.