Trust should always be the first issue when it comes to any relationship. Hmmm. You wonder why they won't 'let' you have a beardie. Honestly, their house their rules.
Beardie's are a lot more expensive, and harder to care for than a ball python. Are you ready for this? Special bulbs, a lot of food, and calcium requirements. It takes a lot of responsibility. I'm not trying to discourage you, but maybe you should wait until you have a place of your own.