You've likely already done this but on the very slight off-chance that you haven't -- have you told her that you're good with (assuming you really are) different days / times weekly? i.e., it doesn't need to be consistent?

In interviewing new Ts (and with former T when my schedule changed), I ran into scheduling problems -- they all seemed to be uniformly perplexed that I couldn't make it at times that worked for them (usually during normal business hours). And, so then it seemed like a major cognitive effort all around to figure out alternate times. I realized then that at some level, most of them seemed to think that clients value consistency of time etc and so, couldn't easily imagine not setting a regular schedule.

Of course, all this may well be moot in your case but fwiw etc.