My 2cents/pence: DS BF'd until 19 months. He loathed the bottle until almost 7 months. When he finally would take it, we still had to hold it for him until almost 18 months old! He could drink from a sippy/straw cup (water) at only 6 months. An open cup of water at 9 months. Eat with a spoon and fork at 1yr. BUT his milk was in a boob or bottle form only! After BF ended he still had to have that bottle for his milk. This lasted until.... ummmm 3 years old! DH and I were stressed at first and tried to take it away then it was so hard and it was his only vice and he LOVED his bottle. We looked at each other and were like, why not? He only took it 1x a day after dinner or late in the afternoon. (was 2x a day at 2yrs) and we always brushed teeth after and of course he never walked around with a bottle or slept with it in his life. So we relaxed about it.
He could eat and drink independently so no worries there, we knew he would stop on his own time and he did at 3 years 3 months. He now drinks his milk from a tea mug and doesn't really drink a lot of it anymore. He is a very good eater as well btw and always was. I think that is important too, so they are not filling up on fast flow bottles and then not eating well, then we would of been more concerned kwim? Our experience, hope it helps.
Aisling x