At 16 I think she should be old enough to cook simple meals now and then but things you could try
Spag Bol etc with red lentils instead of meat they give a nice texture
Use quorn mince and chicken replacement
Cous cous and roasted veg salad
Quorn nuggets or frozen veggie burgers with home made sweet potatoe wedges won't hurt now and then
Jacket potatoes with various fillings
Veg pasta in a nice home made sauce
Veg lasagne
Risotto
Veg fajitas with guacamole
Quorn/tofu and veg stir fry with noodles
Chilli made with chickpeas, kidney beans, peppers, onion, butter beans and any other beans you like instead of meat
Veg tagine
A lot of veg curry recipes out there ( my favourite is chickpea, spinach and sweet potatoes)
you can do great tasty dishes with halloumi cheese.
Take a look at the vegetarian society website and BBC website have some good recipes to try out
I'm not veggie but only eat meat once a week so 6 days are veggie dinners