Glass is 3/8" thickness rather than full 1/2" so at this enormous size, it is too flimsy and does not feel safe.  You will want to add a ceiling mount support arm to the top corner furthest from the wall bracket.  I used parts from C.R. Laurence Co (CRL S910BN; CRL S1BN; and CRL S12BN) to make one. The 4 mounting brackets it comes with are small which likely adds to the instability, so you may want to ditch those and replace them with more hefty brackets online.