First, as others have mentioned, you are not a failure. It always surprises me when mom's say that. No one's kids are perfect and Lord knows we all have our faults. We have some control over what our kids do and how they act, but they are still little people with their own wills and we cannot control their every choice. All you can do is the best you can and the rest is destiny.
I have a 2 1/2 year old son who's a strange eater I would say. At home, sometimes he'll eat everything we give him, and other times he just plays with his food and won't eat any of it. His babysitter says he eats like crazy for her. So one thing we've done that seems to help with eating at meal times is to avoid giving him milk before or with the meal. I found that he would sit and drink all the milk and then not be hungry for the food. So now when he asks for milk with his meal, we just tell him there is no milk and give him a cup of water. Sometimes he cries and throws a fit. Other times he drinks some water and starts eating. We give him at least 16-24 ounces of milk a day with breakfast and during snack times, but never with meals. I think that was a big issue for him with regards to his hunger, or lack thereof.
In regards to what he eats, we do NOT cater to the kids' tastes except for when we're eating something spicy. Then I usually make them something different that they like like mac & cheese, grilled chicken strips and apple sauce or something like that. Otherwise, I put the same stuff on his plate that I put on mine and he eats what he wants off of it and leaves the rest. I ask him to eat his veggies, and sometimes try to take some off his plate and eat them myself which usually makes him want to eat them. He points his finger at me and says "No Mom! Don't do again!" and then he starts eating them, but sometimes he starts trying to feed all his food to me when I do that so there's no real formula I can use to get him to eat.
I would say just maybe cut back on the milk at meal times and try to pack as much nutrition into the foods she will eat as possible. Like when you feed her pasta, make sure it's whole wheat or whole grain pasta. There is pasta made with vegetables that you can buy as well. Make sure the cereal you are feeding her is made with whole grains and is low on sugar. Make whole wheat pancakes and try to sneak some blueberries or other fruit into the mix. And she already likes bananas. My son would have 4 a day if we'd let him. I think bananas are a great food for toddlers!
Kids at this age are funny eaters usually. It should get better with age though. But I warn you, do NOT cater to her picky eating 'cause it can grow with the child. I have a 15 year old niece that is so picky, my brother-in-law can hardly stand taking her out to eat. When we went to my husband's birthday dinner at Uncle Julio's she had a grocery list of changes to her taco plate and when they brought it out EXACTLY as she asked, she still had a problem with it and wouldn't eat it. It's definitely a control issue with her, as it has always been, but her mom and grandmother always catered to her picky eating so now it's just the norm for her.
Good luck!