9th Grade Student Looking to Transfer From Puplic School to Boarding School

Hi all! I apol in advance if a thread of this nature has already been created, I’m still getting used to college confidential! Anyway, I’m a 9th grade student currently attending a public school in Baltimore. I have been pretty dissatisfied thus far, and I’ve been researching alternatives. Despite its cost (plus my parents are still unconvinced), boarding school seems like it would be a good option for me. Does anyone know what the chances are for a student applying for 10th grade? Are they better or worse than for those applying for 9th? Any advice on how to convince my parents or anything else at all would be greatly appreciated:)