Has she refused food lately? and has she moved from that spot in the last few days? I noticed the fine layer of silk, like a blanket, all around her. My B. hamorii made a "silk blanket" when he molted out in the open like that.
Ok, yeah. It could be approaching a molt, but it also could just be well fed. Or both... As said above, watch for that bald spot to darken up. If it does, a molt is right around the corner. After that, and after waiting a 7-10 days, she should be plenty hungry again.
My Albopilosum had a huge butt and bald spot for months before she molted. Her butt was that big I actually thought she was gonna pop! Even when the bald spot turned black it was another few weeks before it happened. One day I noticed she’d made a silk blanket like @Beedrill described and also webbed all the front of her enclosure as though she was putting up curtains for privacy. She then molted 2 days later