First time drug offense?

Somewhat recently, I got searched in school and arrested for possession of a controlled substance (it's this stuff: http://en.wikipedia.org/wiki/Modafinil - I looked around and it is a Schedule 4 substance.. the least punishable, if I'm right). This is my first time ever being arrested, and I'm 15, so what are they likely to give to me in court (I go in a few months) as far as a sentence goes? Also, how long will this stay on my record for? Thanks in advance to whoever answers this question.