<p>@comom: I guess in this case it is better to send an update since the school is not well known and a letter of interest will not likely be interpreted as insincere/redundant/useless flattering. Make sure to mention how she LOVES Princeton, how Princeton is the perfect place for someone like her personally-this “love Princeton” part should be more emphasized than any update that is not on an earth-shattering level (making the national team; winning ISEF; becoming fluent in 3 languages in a month etc), and make sure it is passionate and has her voice in it. Good luck!</p>