Chances for what? The Prep school or being offered an appointment this year?
If you responded positively to the offer for Prep school, then they are considering you for that and I think your chance is pretty good provided you gave a positive response.
Please keep in touch with the regional commander who contacted you if you will accept a prep school offer. He/she is your go-to person and can keep you updated. Sometimes the process takes a while - i.e. they will say - you don't have an offer yet but we are working on it for you - this is positive. Not definite but positive.
Have faith that these Army officers are working on YOUR behalf. They are honest and genuine and won't give you the run around but some times the wheels spin out of their control and you live in limbo for a while.
Good Luck to you!