While she was excellent at Legilimency, after months of practice, her real talent was in Occlumency. She suspected it was because of the sheer number of secrets she had, which caused her to throw all of her focus on keeping Albus from seeing them. Pretty much her whole life up to that point would be completely off-limits. Where it took her months of constant and diligent study to master Legilimency, she mastered Occlumency in a matter of weeks.