I'm 25, and one semester away from my bachelors degree, which, by the way, will be in brass performance. I studied both the piano and French horn through my freshman year of college, winning two piano competitions as a teenager, but decided to specialize in horn. I still accompany occasionally, and I have ten piano students, including my mother-in-law (yes, she pays me), and another lady who I think is 50-60ish.
Admittedly I'm not an obective judge of my own teaching skills, but I like to think I'm pretty good.
I will always be grateful to my students and their parents, who allowed me the chance to make a few mistakes and learn from them. I'm not on par with someone who has a teaching certificate and 20 years experience, but I am a better teacher than when I started 14 months ago. Without parents willing to look past a lack of teaching experience, I never would have gotten started.
If the teacher in question is any good at all, she will adapt to your learning style. Frankly, there's probably not much to adapt to. I prefer adult students, because they take lessons much more seriously than the kids do. After all, it is their money being spent. With the kids, I have to find the right balance between ogre and nice guy, whereas, with the adults, I can focus on teaching without having to worry excessively about motivation.
Having said all that, what is most important is whether she helps you meet your goals as a student. I don't think age or relative inexperience should be deal-breakers in and of themselves. After all, we're talking about someone who is attending one of the most selective music schools in the country. Assuming she answers your questions to your satisfaction, I'd say give her a chance. If the two of you don't jive, you can always look for another teacher later.
Just my advice; worth every penny you paid for it.