First let me tell you that I'm totally lucky - my daughter will eat just about anything. I, on the other hand, was an extremely picky eater. If you let her get away with it now, it might be a problem for you through her early adult years. I truly believe that my health suffered from my pickiness-induced lack of nutrition. Not necessarily when I was two, but when I was older and competing athletically.
When our daughter was little, we talked to our Dr. about it (since I was concerned) and he said that it is physicallly impossible for a toddler to starve themselves. He said to offer her a range of foods, but not to give in to the same thing over and over.
I'm a fan of sneaking veggies in. That is how I learned to overcome my own pickiness. Some things I do:
1) Cut up tomatoes and/or spinach into tiny pieces (you can do a small bag that will last a week) and wrap the cheese or turkey around it so it's still a small bite, but the new food is hidden. Gradually, she'll eat the food in the middle too, as she gets used to the texture and taste. If she spits out the food in the middle, try cutting it even smaller. I've had to reintroduce tomatoes to my daughter this way a couple of times. Now she's back to eating big chunks without any other food.
2) If she'll eat soup you can sneak pureed veggies in with that. For example, add pureed peas (or pea baby food) into tomato soup.
3) If she'll eat Mac N Cheese, buy a little broccoli and add a little bit of the very tops - cut it off high enough that it falls into the pasta like sprinkles. Be careful the first few times not to do too much or it will overwhelm the taste and she might reject it. As she gets used to it you can add more and more.
4) My favorite thing in the world is a little product called "Super Tots" by Ian's foods. I can only get it at the health food store, but they're french fries with carrots, spinach, and cauliflower added in. They're doing all the work for me!
The trick, for me, was to get a little used to the flavor and texture without being overwhelmed by it.
Hopefully my tricks will work on your daughter. I definitely use some of this sneakiness on mine and we have great results. She'll seriously eat just about anything now and she's two. The other night she ate an adult size serving of the lasagna I made, including the artichokes I hid in the ricotta cheese!