Power play, for sure. It's not bad because, yes, it is all they can control. But, if she's allowed to 'win', she'll test you more than necessary on so many other things until she thinks she gets the same 'positive' results (whatever it is she wants). I am amazed with the amount of misery our boys will tolerate because they think they'll convince me to eventually 'give in'. Often they think this because they've been engaging in a behavior for some time that I was unaware of before it became a problem.
On a side note, imagine if we got everything we wanted immediately, or even after some suffering! I can think of multiple crushes in the past I'm grateful didn't 'work out' for me. Ug!
Giving choices is a good, positive thing to do. My 18-mo old doesn't like a lot of food, but we've also learned he wants to feel in control and challenged. SO, if we help him use his fork and try to conquor that challenge, he's excited to eat.
Otherwise, I have heated the same meal up to five times, serving it only (no snacks) until at least half of it was eaten. They came to learn it really tastes better the first time.
I have also learned not to put much AT ALL on their plates. They have a much easier time stomaching food, or even asking for more, when they don't feel overwhelmed with the prospect of eating a large amount (especially if your first child eats well, like mine).
Yes, have you tried mincing her food? My son has very few teeth, no molars, and so will only eat minced food very well. Even sandwiches, I'll chop up.
We also don't allow fussing. Immediately unpon uttering a fuss, they are given a negative consequence (very thorough hand spanking). Most people don't choose this kind of consequence, but there are many. They very quickly learn that being pleasant is happier. Now, if they choose not to eat any of their meal, they sit pleasantly until everyone leaves the table and their same plate is then offered at the next eating time. It also teaches stewardship, not wasting the food we've been blessed with.
HANG IN THERE and yes, give yourself some space when you need it. God bless.