That is interesting. First thing is that every dog is completely different than the next so you cant compare exactly. I am by far no expert here but I do know that dogs dont know how to not love for the most part. I mean look at the abused pups out there who still try and just love their abusers. I would guess that your girl is just not as cuddly as the rest are. The fact that you are asking the question tells me you are loving her enough and doing what you can to make her happy. Anyone who didnt care wouldn't be here. I wouldn't stress over it, just accept her the way she is and know that she loves you even if it isnt the way you expect. You say you have had her for 5 months, who had her the first 4? Maybe there is some kind of issue with her from the previous owner?
By the way, welcome to the boards! We need pics please.