The protagonist of Tracy Chevalier's novel Girl With a Pearl Earring is a sixteen-year-old girl (the one mentioned in the title, of course), so the story was presumably written with a young adult audience in mind. The reading level is only 5.4, so the actual writing and vocabulary are perfectly suited for young adult readers.
The question is whether the subject matter is appealing to that audience, and the only reason there is some doubt is that the story line is heavily integrated with history and art. Sometimes a book that is a little more "educational" does not seem as appealing to read, so your question is a valid one.
This is a matter of opinion and others may certainly disagree, but the story line seems compelling enough to attract and keep the interest of most teen readers. Because most of them have had an art class at some point in their lives, they have probably at least heard of Vermeer, and the idea that he was inspired to create a painting as a tribute of some kind to a young girl is intriguing.
While art elements are a significant factor in the story, readers will find plenty of drama to overcome any dissatisfaction about having to read so much about painting. Griet's story is compelling on many levels, as she is an orphan, a maid, an object of men's affections, and a young woman who knows what she does and does not want out of life. Her story is interesting, and the fact that it is a "what-if" story about a real and recognizable painting is intriguing.
What might be more off-putting than the story infused with history and art is Chevalier's writing style. While the vocabulary she uses is not particularly complex, as I mentioned above, her writing style is full of imagery, description, and figurative language. Although many young people enjoy and appreciate this kind of writing, others do not enjoy it nearly as much.
Consider the following passages from the novel.
I heard voices outside our front door--a woman's, bright as polished brass, and a man's, low and dark like the wood of the table I was working on. They were the kind of voices we heard rarely in our house. I could hear rich carpets in their voices, books and pearls and fur.
This description is rich with figurative language and it certainly draws a multi-sensory picture of these particular voices. For those who appreciate this kind of description, this novel is a perfect match. For readers who prefer their reading to be a little more straightforward (or less "flowery," perhaps), this novel might not be the best choice.
On the other hand, Chevalier is able to convey some ideas that teenagers understand, such as this observation:
“You're so calm and quiet, you never say. But there are things inside you. I see them sometimes, hiding in your eyes.”
Teenagers are quite adept at both keeping some parts of themselves hidden and looking for hidden depths in others. To that extent, then, this aspect of the author's style might be quite appealing.
Finally, though the majority of the story is rather straightforward and relatively practical, there is also an air of veiled mystery in the characters' thoughts, and that is reflected in the language of the novel, as well. She writes:
It was not a house where secrets could be kept easily.
Those who truly love mysteries will not find this story satisfying, but mystery is present.
In short, the history and art elements of this novel might be less problematic for young adult readers than the style and language in which the novel was written.