I am 31 and have been a lacto ovo vegetarian since I was 14. I'm the only vegetarian in my family and my mom really resisted at first (cooking my fav meat dishes every night, etc.) but then realized that it was not a phase. She started experimenting with cooking and I think it benefited the entire family, health wise.
Typically, ethnic cuisines are waaaayyy more vegi friendly and exciting to cook and eat. Standard "American" fare is meaty, fatty and generally not healthy. For example, rice (preferably brown) and beans eaten together make a complete protein. What can you do with rice and beans? Think Mexican, East Indian, Creole, etc. There are LOTS of possiblities. You can even go Italian with a short grain risotto rice (arborio rice) slow cooked with veg broth, veggies and cannelli beans. YUM!
Even if your daughter goes back to meat, that does not mean you cannot continue cooking vegetarian meals for your family. Good luck!