Still on newborn nipples

So, my daughter is officially 6 months and she is STILL drinking out of stage 1 nipples. If I change them she just chokes on her milk..

She understands the concept of drinking from a cup from watching us so we got her a 360 degree sippy and she can't suck hard enough. We've also gotten a regular sippy (both for 6+) and she cant do that one either.

I'm afraid she'll be on newborn nipples and bottles FOREVER. Which I hate because my mother in law AND brother in law both have almost 4 year olds that still drink bottles and their teeth are protruding out of their mouths. They refuse to let it go.

I know she has til 12 months..I just feel like she isnt progressing with it..