Has she shared why she wants to go vegan?
Does she like peanut butter, almond butter, cashews, sunflower seeds, things like that, or chia seeds or hemp seeds? I eat a lot of toast with peanut butter and jelly on it. How about avocados? Does she like smoothies? How about fruit eaten by itself or in a fruit salad, . . . watermelon, apples, oranges, bananas, pineapple? Grapes, raisins? Will she eat things like carrot sticks, celery sticks, and cucumbers cut into sticks or slices (my boys mostly avoid cooked veggies, but will eat things like that). Spaghetti sauce with pasta is good.
I'm sorry. . . my kids are waiting for me so I'd better go! but I'll be glad to talk more.
eta: I took so long to decide what to write that I see that there are already other replies. I'll go ahead and post mine anyway.