Can you suggest some good vegetarian diet for 13 y/o girl?

Be careful: I trust this is what she truly wants to do -- if an adult is forcing it on her, she will resent it for the rest of her life. She also needs to know that she must supplement -- even non-vegan vegetarians tend to become B12 deficient, and despite all the hucksters, she'll have trouble getting enough iron, calcium, iodine and some of the others. She needs to have a serious talk with her physician.

Vegetarian: Make sure you get enough protein in your diet- eggs, dairy, nuts, soy, tofu, and other foods can be a good source of protein if you don't eat meat. Take a multivitamin with iron (for teenagers or women) Eat a variety of foods- whole grains, vegetables and fruits. You will get incomplete proteins from corn, rice, and beans, but combinations of those foods will give you a complete protein.