Awesome advice here!

The only thing I can offer is my own experience - although not exactly the same, I did (and still do) have a problem with different sensations in my mouth.

I can't hack tomato - oh CRAP, it's so wrong. Hard on the outside (to me) and so squishy on the inside...bluuuerrgh. I grow tomatoes and make a killer sauce but can't actually eat them.

It took me till nearly 25 to try to so something about it, and all the while everyone was on my back about being picky, or too skinny or whatever...and that just made it worse because I felt like all eyes were on me everytime I ate.

It might very well be a gagging thing by the looks of it - have you talked to her about exactly what is going on for her? Could you give her a list of things to choose from like -

I'm scared I will choke
It tastes funny (sensations etc) or
It makes me feel.....

I dunno, I'm no expert I hope you get some answers xoxoxo