If she's liking it at three months, I'd say she'll probably stick with it...I hope so, anyway.
Amelia is sneaky. I'll put it in her mouth and hold it there for a few seconds, to give her a chance to latch onto it...she'll keep her mouth wide open around it, like she doesn't even want to
touch the thing. And if I'm persistent about it, she'll finally close her mouth and start sucking on it...just long enough for me to let go, and then she *immediately* turns her head to one side and spits it out!

It would be downright hilarious if it weren't so irritating when I REALLY want her to use it!