First feeding attempt, total disaster.

[RobNJ]

Any advice for getting her to eat tonight?

I'd wait a few days to a week.

I'm a little concerned that she missed that many times. I hope she is healthy?

I don't know anything about your snake, so can't comment on health...as far as missing her food goes, some young ball pythons can be a bit uncoordinated and not have fully worked out the aim of their strike. It's also a possibility that it's in shed. There's also the possibility that it was striking defensively.

Also, she yawned several times while being offered the mouse, does that mean she's interested in eating?

But I would lean towards the strikes not being defensive strikes, and that she just missed the mouse, and the 'yawns' were her realigning her jaw...they are not a sign of hunger.