Niobe is a lovely thing. Good luck with your first Clematis. Two points come to mind though. Clematis like reasonable light and your garden looks rather shady. I see ferns and hostas. Secondly, dark colours like Niobe get rather lost in shadow. I would probably have chosen a white or very pale colour. I’d keep a close eye on it and be prepared to move it if it doesn't look happy. I’m sure Niobe won’t be your last Clematis.

Clematis 'Guernsey Cream' might suit that area.

On siting, Floral is correct, clematis like their heads in the sun and their feet shaded (mulch or ground cover).

Thanks to everyone’s input I’m going to move this clematis about 25 feet to the left along the fence. It will get a good bit more sun in that spot.