It will be okay, but you could fit another one. However, what many people don’t realize is that there is always the risk of incessant bullying, especially with just two goldfish.
I don’t think having another is an absolute necessity is what I’m saying.
If you want another one, get it. If it turns out to be an incessant bully, then prepare to rehome, whether it’s to another tank or back to the fish store.
Have some autonomy and decide for yourself; don’t let others make it for you.