“We’re making this the Juilliard of the West Coast,” she says, without a hint of braggadocio or hubris. The claim might seem grandiose, but you underestimate this woman at your peril. The CJC’s founder, president, and dean of instruction (and a formidable pianist in her own right), Muscarella has patiently shepherded the institution since she launched it 20 years ago in cramped quarters above a French cafe on Shattuck Avenue. Long known as the Jazzschool (the name still used for the CJC’s popular community music school), the nonprofit 501(c)(3) corporation took on a new identity in 2014 when it earned accreditation from the National Association of Schools of Music.