I think you should do what YOU think you should do. If you feel her comfort sucking should be soothed and she gets better sleep and so do you, then so be it. I haven't seen a teenager yet with a pacifier (unless you count that horrible time in the early 90's when Flavor Flav tried to make it cool or unless you count ravers
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Ava's got one and I am not making a big deal about having it gone by 1...eventually she'll get rid of it, but it soothes her and she's happy why not? It's your decision ultimately, if you think it might be a problem later, then minimize the usage. Otherwise doooo eeeet