Startail - I was like your DD. from the age of about 12, I gradually added more and more things that I eat.
I still have my foibles - If someone dishes me up tinned spaghetti, I will happily eat it, but ONLY if it has been put in a separate bowl. And if it hasn't, then I can't eat anything it has touched and made soggy. I still can't get over that one. I still can't tolerate ANYTHING with coconut in, or liquorice / fennel / aniseed flavour in. Can't cope with 'fake' banana, strawberry or mint flavourings, but love the natural versions of them. Can't eat eggs except fried - and it was only 3 months ago, at 31, that I managed to start eating the yolks! 
There's probably other fussinesses I haven't mentioned too - but it's a far cry from when I was younger and my diet consisted of plain pasta, plain rice and plain chicken and sod all else.
I have serious issues with food, but they are improving year on year. Certain textures and tastes, though, I will never be able to 'get over'
Pushing me as a DC would just have left me hungry, and whiny and grumpy because of hunger. I was hospitalised rather than eat mushrooms, for example, as a 10yo DC - my mother insisted on cooking 12 dinners in a row with mushrooms in, and if I didn't eat them, she would store it, and serve it for breakfast the next day, cold, and lunch, and then a different dinner including mushrooms that night.
It didn't make me eat mushrooms - it made me malnourished.
I finally started eating mushrooms at age 18, when I realised that for DD to not have issues with them, I had to eat them. In front of her. And look like I liked them. It wasn't until I was about 25 that I would CHOOSE to eat mushrooms. I love thm now!
But as a 10yo? I would sooner have starved (literally) than eat anything a mushroom had even touched.
I have Autistic traits and severe sensory issues. Food IS a problem for me, but I am working on it.