You may have to accept that art may not be her special EC for college admissions, and if she just finished freshman year, an obvious new “thing” may not yet have appeared.
But I understand your underlying concern about ECs in the college application process. I was sorry my D was slow to pick up ECs in boarding school, particularly avoiding “leadership” positions. She did not continue with her musical instrument because of logistics and the offerings at her school.
From time to time she and I discussed this in a low pressure way. I was able to show her, for instance, that two undertakings she thought she would do senior year, while fabulous, would come too late to put on college applications.
Her ECs ended up very modest. She was a mentor to a new student and a general member of an organization. She also did a term abroad. She also really wanted to enjoy her HS years and cultivate social relationships. She and her friends are going strong even though they are all scattered at different colleges.
Even though she had and has no intention of majoring in Art, that was her primary focus in HS (ironically the opposite of your D but the particulars are irrelevant). Her goal was to take every art course offered and I think she ended up missing only one. Art was definitely her passion. She submitted a portfolio to most of the colleges to which she applied. Perhaps your D will end up with a special project in her new field of interest.
We were happy with her admission results and she received much more merit aid than we expected (which was none). She’s a great kid. Some AOs saw that. She is happy where she is, having new goals, developing new friendships, and having just the right amount of challenge.