1). What’s her argument
Her argument is to persuade people to search more, to follow the curiosity that you have since you can’t know more if you don’t know it’s existence. Curiosity takes form after you acknowledge a subject’s presence, and therefore, it is important to follow the curiosity about things you already have, to lead to new questions that may help you discover new information that may give rise to more questions.
2). Quote that supports your contention that 1 is true
“You can’t be curious if you don’t know it exists.”
3). Your interpretation of what 2 means
I believe the quote suggests what it says: that curiosity and the want to know wouldn’t exist if you don’t know that it exists. Without knowing that something exists, people wouldn’t feel the need to understand where it came from, what it is, why it is important to them. If the thing they are curious about doesn’t exist, there is no way to start asking the questions.