When determining your character’s ability scores, increase one score by 2 and increase a different score by 1, or increase three different scores by 1. Follow this rule regardless of the method you use to determine the scores, such as rolling or point buy. The “Quick Build” section for your character’s class offers suggestions on which scores to increase. You can follow those suggestions or ignore them, but you can’t raise any of your scores above 20.

The lifecycle of a dragon has a magical component. You are an adult dragon between 300 and 500 years old. Dragons increase in size slowly over hundreds of years eventually becoming gargantuan if they live long enough. A dragon’s natural lifespan is around 1200 years although some live much longer.

Dragons tend to the extremes of alignment based on their subtype. You are not typical of your race and may choose any alignment.

As an adult dragon your size is huge and you will continue to grow with time, becoming gargantuan around 500 years old. 

Your base walking speed is 35 feet and your fly speed of 50ft.

You have a dragon breath weapon and resistance. Choose one type of dragon from the Draconic Ancestry table. Your breath weapon and damage resistance are determined by the dragon type, as shown in the table.

Starting at 3rd level, you can use your action to exhale destructive energy. Your draconic ancestry determines the size, shape, and damage type of the exhalation. When you use your breath weapon, each creature in the area of the exhalation must make a saving throw, the type of which is determined by your draconic ancestry. The DC for this saving throw equals 8 + your Constitution modifier + your proficiency bonus. A creature takes 3d6 damage on a failed save, and half as much damage on a successful one. The damage increases to 6d6 at 6th level, 9d6 at 9th level, 12d6 at 12th level, and 15d6 at 15th level. After you use your breath weapon, you can’t use it again until you complete a short or long rest. This will be selected when you choose your draconic heritage. 

You have resistance to the damage type associated with your draconic ancestry. This will be chosen with your draconic ancestry.

You can speak, read, and write Common and Draconic. 

You have darkvision to 60 feet and 30ft Blindsight.

 You are proficient with your bite and claws which counts as a natural melee weapon. Your bite deals 1d10+ Strength Modifier piercing damage while your claws deal 1d10+ Strength or Dexterity Modifier slashing damage.

You have begun to master your innate magical abilities and as such you can, as an action, polymorph yourself into any medium or small humanoid you have seen.