C.D.
Each baby is different to some degree. You don't have to rush anything regarless of the ped. says. It's completely natural and normal for a little one to need sucking for 2 yrs or more. They need it for the formulation of the teeth, palette, tongue, the jaw, - the whole mouth which is still forming. (Just to mention one aspect.)
Women have always nursed their babies for 2 to 3 yrs for thousands of years. I know lots of people gasp at this, but it is normal. (Personally I couldn't go there; after nursing gave a bottle) But I have known lots of women who do or have.
When I saw that my little one was needing the bottle less and less and pretty much loss interest in it, I would say to them, "we're going to throw the bottle away in the garbage soon, then it'll be gone and we'll say bye-bye to bottle." I'd say it for two or three days so they'd start getting the idea. By this age they knew where the garbage pail was and that once we put it out it was gone. I'd have them throw things in the garbage, so they knew. Then when the child was ready, I'd have them throw the bottle in the garbage and say good-bye bottle we don't need you anymore, bye-bye. - something to that affect. - So they threw it away and said goodbye to it.
I did this with all four and there was never a problem. One of them continued to check throughout the day as to whether it was still in there or not, but not once took it out, she'd just look and then walk away. Of course, each one was ready to do this. Each one of them was over 18 mos. It was around 2 years- some a little younger, some a little older usually by just a couple mos. or so.
Hope this helps.