Nope. The real queen is a creator of this world - Loren Faust. Also there's old russian legend, that Sun and Moon (Solntse and LunA) were daughters of... DUN-DUN-DUN, of Chaos! So, if I'll accord to this legend, Discord is a real king of Equestria but his daughters noticed, that he was freakin' bad ruler, so they took over... WAIT, OH SHI--
Well, technically speaking there's two princesses, now up to four, so technically that makes Equestria a principality. Once again, the Nostalgia Critic's femininity-shaming leads to him missing the point. Just like Sailor Moon.