Forum are full of people who stick around, people who visit every once in a while but not frequently, as well as members who only come on for a question or two, maybe even stay for a little while, then disappear.
I hope she has full support by her parents in her decision to purchase a medium sized bird! I've owned birds for just a smidge over half my life (not saying much, considering my age!

), and I know when I was younger, I probably shouldn't have had birds. I wasn't aware that avian vets existed, let alone lived close to one (town population 90. One traffic light, and not a red, yellow and green one at that!), it took me years to figure out what a healthy diet really was made of (information back when I first got into birds was horrible!), and I really didn't have any real support from family members. In fact, my grandmother kept joking about how the birds were dog or cat food and that how 'they' will eat one of the birds. She still does so ocasionally to this day... don't mind the fact that my very first budgie that I had was killed by a cat at her house. The situation was somewhat unavoidable, considering the circumstances...
If she has full support by her family, I not only envy her, but would encourage her! Especially if she has any ideas about where she will be after highschool. College? University? Social life?
If she doesn't have that support, then yes, I'd have to agree that it may be better to wait until she could get a job of some sort (part time? after school? neighborhood work?) to pay for everything herself. It would make things so much easier!
More or less, it doesn't hurt to plan out your life if you have pets! And especially, parrots!