Your Pomeranian, Bella, will be as picky with food as you allow her to be. She is not being a "bad" dog, she just needs some reinforcement training. Being the runt of the litter most likely did cause Bella to act this way. The smallest dogs are almost always pushed aside.
Without someone keeping a very close eye, the runts of litter often die from starvation or dehydration. So, poor little Bella probably had to fight for every drop of mom's milk that she got!
Rescue dogs are also known for this behavior. In addition, dogs who do not feel secure that their food is safe will move it to another room, one where they feel that their food is "protected".
This can happen if the kitchen is a very noisy room, if there are other dogs in the home and the Pom feels as if she needs to compete for food or if people sit or walk too close to where the dog food dish is.
Bella will eat where you want her to. She will do this by your non-stop efforts to show her that no other option is acceptable.
It is also important that she feels very safe in the area that you wish for her to eat. Please make sure that it is in a very quiet corner of a room. It should not be in an area where people walk by or near an open door.
When she eats, she should feel secure that no one is coming close: an action that she may see as a threat to her food being taken away.