I need suggestions on pacifier breaking!?

My daughter is 17 months old.. she loves her soothie (her pacifier).. She transitioned VERY well from a bottle to a cup.. no problems at all...I took the bottles away completely when she turned 1. Now I'm having trouble with the pacifier. I try to only give it to her during the night time or during naps.. but the problem I am facing is that I also have a 6 month old who takes a pacifier... I will take my oldest daughters away and she will end up with one anyways.. she steals it from her little sis!.. the only idea I can come up with is to only let my youngest have her pacifier when she naps and sleeps at night also.. but I feel like I'm taking her infancy away from her...But then again she doesn't really even use the pacifier except to fall asleep so it would be ok, right?... I'd like to break my 17 month old completely from it ...is it too soon???.. She isn't really talking much and I think without the paci she may start to say more.