Is it the musician or the instrument?

to start im in my middle school band, we are broke, we suck, the school refuses to help, all I can do is except it. so im fairly new to bass clarinet at four months, previously i played tenor saxophone for a year and a half and alto for a year. I can play great on low i find all the fingerings easy and the embouchure while being very tiring and makes my lips sor, I can manage. my one difficulty is high notes, I have no clue if my clarinet is broken or I just suck. I can play every note up to b flat then the bass shoots up and squeaks if I go any further. the bass is most likely very old and it’s a lil gross looking on the inside but everything otherwise sounds pretty nice. is it me or is it the instrument?