Is this a normal sized poop?

Most vets will let you email them these pictures

It really varies for my dragons. It depends on the dragon, how long it's been since the last poop, how much they ate, & what they're eating. I'd go ahead & ask the vet if you are worried, but how is your dragon acting? If they are acting like normal I wouldn't worry too much.
When I first started caring for dragons I would worry about the size of the urate sooo much! I'd worry if it was big, little, yellow, Everything! 🤗

yes normal, maybe slightly large (potentially 2 meals worth of poop stored). more concerning is the color of your urate. typically pinkish brown on the urate suggests parasites, so if you can, please get your bearded dragon checked by an exotic vets for parasites.