She didn't have to intend to kill him with a knife specifically for it to be premeditated. The crime scene tells you something happened that was very violent and messy, and that PERHAPS didnt go quite as JODI planned; but she did not need to know exactly how Travis would react and where precisely he'd be able to crawl to etc etc for it to be premeditated.
But, don't you have to prove either
1) why she used a knife instead of the stolen gun
or 2) how she premeditated with the knife [eg. prove she brought the knife] ?