Quoting NicoThunders:" Because she's "too old" for bottles. Jeff asked me the other day how old Fi was when we stopped giving ... [snip!] ... 6 months but if it weren't for Jeff I'm sure I'd still be letting Fel have a formula bottle at 3, heh. Yes I know I'm horrible."
If she takes it in a sippy I'd tell him to shut up
She's had growth issues and it's not like she's that old. Maybe just start to slowly phase it out, like only half as much in one bottle at a time until they're all 1/2 as much, then drop one of those at a time?