Could this become a habit for my 11 week old?

he might just be hungry, when my baby is hungry she starts sucking on things close to her mouth. just pull that thumb out and put in a bottle, or a , which ever you are doing. my baby wont even take a pacifier anymore, which i thought was a good thing untill we went on a car ride and i had to pull into a gas station and sit in the backseat and feed her for 10 minutes just to quiet her :(