I had TONS of untactful nudges from my mum when DS was little because suchabody's DC who was only weeks older than DS had already given theirs up. I DON'T GIVE A FUCK... suchabody's DC was also a little sh*t, do you want DS to behave likewise.
Any way (rant over) ex-P (DS's dad) and I decided that DS could lead when the dummy should go. He only ever had it for bed from around the same age as your DD but only felt ready to give it up on his 4th birthday having slowly weaned himself off it over the previous 18 months or so i.e. not wanting it every bedtime but knowing it was there just in case IYKWIM.
He made the decision and did it happily (with slight woeful glances at the bin as he walked away!!)
You know your own child. The dodo fairy came when dd was around 2.5, dd used hers only for nighttime (albeit around 20 of the fuckers in bed with her). She used it during the day from about 3 weeks onward and TBH it was the off switch. Go with your instincts, personally I'd say once they get to 7 it could be a problem.
She's your child. If you feel she shouldn't have it then you can work at it, if not you ca decide when.
ds had his until nearly 3 I think and not just for naps, although he was never allowed to speak with it in. Even after that he shoved all manner of things into his mouth to suck on, I think some kids are just more suck-y than others!