What motoguzziman said - I second that. I'm 84 and do all my own wrenching on my F3L. Not that hard if you know which end of the screwdriver is the handle. And this forum is a wealth of good info.
Before you plunk your money down, have her try the various models. For starters, you sit differently in each one. I bought an F3L because you sit lower and the ergonomics are more adjustable to suit me. Also, the F3 is a lot easier to work on due to far fewer Tupperware panels. But let her try and decide - nothing worse than an uncomfortable bike.