Most small BP's dont eat because they are either in too large of an enclosure or they are too cool. Sounds like you have a hatchling which I wouldn't put in anything larger than a 6 quart tub. Also if you room temps drop under 80 degrees that may cause them to not eat.

When I hatch a BP I dont sell or give it to anyone until it has had 4 consecutive meals so I know it is an established eater. Moving it around too much before it is an established feeder can cause some of the problems you are experiencing. If you have her in a glass tank she is probably way too nervous to eat. I would get a small 6 quart tub and put her in there with a tight hide and small water bowl and then in the tank if thats where your heating element is. Security is more important to BP's than eating. Also dont try to fed her day after day as it will just stress her out and dont handle her either. If she refuses than wait at least 4 days to try again. The snake must feel safe and secure before she will eat. Also try leaving a live mouse hopper with her in the total darkness. They are much more secure at night and dont disturb her. A mouse hopper can not do any harm to a snake so dont worry. I have left them over night with stubborn hatchlings and many times that does the trick.