'her arrival at this moment stuck me as rather strange.'why did the narrator find the young lady's arrival at that point of time strange?

When the young lady entered the shop everyone including the American who was searching for the flowering this was the lady who was staring at the display of the Undertaker's shop in which nothing of her interest was kept it seemed very strange as she was having no sign of arrival at that movement seemed to be very strange as he thought that if she wanted to come in the shop then why she didn't came into the shop earlier and kept on staring display of the Undertaker shop for a long time