feeding my 12wk 20lb puppy

Question
should i be feeding her 1 or more cups of food 3x@day or more

Answer
A cup may be too much.  Your dog definitely should be narrower at the waist than the hips and chest.
You should be able to easily feel the ribs, but not see them.  Each dog is
different.  Standard recommendations are a good place to start, but each dog
must have its food adjusted to its individual needs. Here is a link to a good illustrated guide,
http://www.longliveyourdog.com/twoplus/RateYourDog.aspx