Approximately how long would it take to learn the Cello?

I have music experience but its all in concert band instruments, flute, piccolo, and trumpet, so I can read notes and I'm not tone deaf. I cant stand band anymore because we have a new band teacher that instructs like a dictator. So I was wondering about how much time I would have to take private lessons to not look like a noob in orchestra cl (me being a junior I feel awkward looking dumb in front of freshman)