The nice thing about eventing that a horse's heart is almost more important than its conformation. That said, your mare is definitely racing bred. It has the low tied in neck that makes running so much easier. But, it makes it harder to lighten the forehand and carry herself higher. She has long and slopy pasterns which can mean they are a bit more prone to stress injuries, But I hav seen worse stand up to high level competitions. She has a very sloping croup/loin making it a bit harder for collection.
That said, some pounds and correct training will improve the correct muscling and will really improve her overall impression. There is no reason she couldn' do low to moderate competitions. Beyond that will greatly depend on her herat and desire to please you.
I'll never forget the USCTA horse of the year on year. He has a short bull neck, post hind legs and a club foot. But his heart was so mighty, he was a big advanced winner.