19 month old sleep question

I recently took away my daughter's bedtime bottle (so no more bottles). She hasn't had any issues falling asleep but she has started waking up between 4am-5am (previously slept until 6:30-7am) and/or in the middle of the night (was sleeping through before this). Any suggestions on how to get back on track? I still offer her milk in a cup before bed but she only takes a fe

w sips & I offer a snack like yogurt before bedtime routine so I don't think she's hungry.