There is plenty of video of Jana playing basketball. Sure, the quality of opponents is not super high but believe me, she has shown enough to warrant the optimism being shown on this thread!
I think the reason so many have Jana starting even though she hasn't proven anything yet, is partly our optimism over her future, and partly because her likely competition if anything has under-performed expectations. Ice, Ayanna, and Jana probably came in with roughly similar expectations IMO. Two of those have a one year track record that doesn't rule out achieving at a high level, but has dampened expectations somewhat. Jana hasn't so much jumped ahead of them, as they fell behind.
Of the smalls, we have a couple of players who have proven something, being pretty good in their freshmen season. But KK and Ash have tons of very high level competition this year, including two players who were better than them in their freshmen season (Azzi and Caroline), and two incoming frosh with similar HS rankings (Allie and Morgan).
So do I think Jana has as good a chance to start as KK or Ash? Yes, and I think she will be very good, but frankly as the only player over 6-3 her path to starting is much easier. For positions 1-3, I see Paige and Azzi (if healthy) as locks and as many as 7 good candidates (including Q) for that third perimeter spot. Being as good as KK and Ash were last year, even with some significant improvement, may not be good enough to be at the top of that very good list of competitors.
In the backcourt we can be near certain that whoever starts will have to be very good, but at the 5 we are far more dependent on Jana being the real deal, unless we pull in a top portal transfer.