3ds xl upper shell won’t fully close/slide up? Any tips/help?

When I try to push the upper shell up, at first I couldn’t get it to click all the down around the edges and slide it up, but after a while of repeatedly trying, I managed to make them click down around the edges more completely.

However, now when I try to slide it up all the way at the hinge/spine side, it won’t fully slide up, leaving like a millimeter or 2 of space left. And when I try to slide and push it up any more, it doesn’t seem to budge or move any further, so I can’t put the screws back because it’s not fully in place yet.

I’ve been trying to put this thing on for hours, repeatedly taking it off or on. It doesn’t look like anything’s wrong with the shell, either, at least from what I see. Am I trying to put this on wrong? What should I do?