Forward: You've Taken Me Higher Than I've Ever Been Before
So, you want to hide a planet. Well, hold on there, Little Billy, because hiding an entire planet isn't as simple as just slapping "this planet is totes secret, bro" into the description. It takes a little something we in the "biz" like to call logic. Sure, you can do that, but saying it's a secret won't suspend disbelief. You may also argue "oh, Ryan, you unlikable little hooligan, this is Star Wars. People run around swinging swords made out of plasma and can do crazy stuff with their mind."
And that would be a fair point. Ish. But to paraphrase Shamus Youn:, having different rules doesn't mean no rules. If you can't reasonably justify why your planet hasn't been found by literally anyone else in the entire history of the galaxy, it isn't hidden. It can't be.