yeah, i stopped sterilizing by 10mths.
we don't have the bottle now (sry), but i swear i have a little self-weaner! refused the boob at 6mths (despite nothing being wrong) and using a straw full time by age one. (sippy cup had no success here)
i definitely don't think you have done anything different than i, all lo's are different. just keep at er...she'll get it.
since she is a toddler, have you thought about transitioning her to just a regular open cup?
a good place to practice this, is in the bath. lifting a cup of water to her mouth and letting her practice drinking (do it at the start so the water is still clean-or fill up in sink and hand to her). who cares if she ends up wet! lol.
i don't think it matters how she gets those liquids in at all. if it bothers you, and you wish to change it....there are probably some ways to entice her to use it, or maybe she's the type to go cold turkey? i think if you are both agreeable to your routine, why change it?
hope this helps
sami
we aim to get 16oz of whole milk in a day---not counting cheese and yogurt etc.