G.B.
None of the kids in my child care center can use tippy cups until they are a bit older, most were older than 11 months. I would get her the soft top ones that are more similar to a bottle. She still shouldn't have the ability to suck a straw yet and that's the action she'll need to develop first. To suck a straw she needs the ability to suck while holding her breath and then hold the fluid in her mouth then swallow. She is most likely still sucking and swallowing like on a bottle. It will probably happen in the next couple of months so keep working with her.
To the ones asking why cups at all:
The reason mom's use tippy/sippy cups is so they don't have to clean up spills and change kids clothes every 5 minutes. My time is worth something and I chose to play and have fun instead of cleaning up avoidable messes.