My dd decided to be veggie at the age of about 7. She's now 11 so people are finally realising it's not a phase.
I'm veggie but my DH and the three DSs eat meat so I often do a meat option and a veggie option.
As a family we (or rather they) eat meat just once or twice a week. DH is a great cook and doesn't mind doing the veggie option. It's worth having things like these in the freezer. Tivall are expensive but they do really nice veggie stuff including hot dog sausages.
It's also worth going to the health food shop now and again for veggie ideas.
I use lots of beans, lentils and nuts. They're good for protein. Rose Elliot's Bean Book is very good but my favourite veggie cookbook is Leith's Vegetarian Bible which is absolutely great.
It doesn't occur to me to cook meat (dh does that) so all my meal ideas are veggie anyway.
Some general rules -- Puy lentils are lovely. Much more tasty than orange ones. Otherwise you'll have to experiement with different beans as they all taste different. Some are sweeter or nuttier than others.
Frijoles or refried beans are good. Soak pinto beans overnight then boil. Then fry some finely chopped onion, add the mashed up beans and fry them. Add a tin of tomatoes and some chilli, a slug of oil and you have frijoles. This can be served in tacos or burritoes with cheese, salad, soured cream and salsa.
By the way, good on you for taking this so well and rising to the challenge. Excellent mum work!!