6 month old, been told by MIL & SIL to start eating rice?

I would say follow your instincts If you don't think she is ready then she is more than likely not. I personally think spanish rice `anything like that might cause belly ache due to it being spicy or just having different ingredients in it. If you really want you could blend some actual rice with like green beans or squash (But your baby doesn't need rice). Good luck do what you think is right she is your child not there's!