Odds of Hanging On
This career is both wonderfully fulfilling and horrifically draining. You'll know pretty early on whether you can hack it or not. Some people will figure out during their studies that they'd much rather be a veterinarian.
Other people will figure it out after a few years of not even booking an unpaid recital at an old folks' home. For some, it's the twelve-hour rehearsal blocks that defeat them; for others, it's the unfortunate breakdown of their vocal chords. There's a lot going against you here, so if you want this career, you'd better work your cummerbund off.
Even if you make it through that, you have to make sure you're building your reputation as a great performer, not a great big jerk. When you book jobs left and right, you should still treat everyone with professionalism.
The opera community is small and strong, and you'll run into many of these people on a regular basis: at auditions, during workshops, and probably even at the grocery store (artists tend to flock together). Do yourself a favor and try not to ruffle any feathers.