You're a dragon. Choose your desired ability score increases. The first choice increases by 2, the second choice increases by 1. While the system doesn't stop you from stacking these increases it is against the rules to do so. Please distribute these increases in different stats.

Dragon's come in many forms. They live long and grow at varying rates. All dragons are different. You can choose to be small, medium, or large to match the age and stage of development you wish to relay.

You have draconic ancestry. 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.

Draconic Ancestry

Choose a draconic gift. You can either gain Darkvision out to 60 feet, Natural Armor of 13 + your Dexterity modifier, or proficiency in two skills.

Along with your true dragon form you have a humanoid form. Both of these forms are determined when you create your character. You can change between these forms as an action.

While in your humanoid form your size is determined by the race of humanoid you are becoming. As a humanoid you have access to your breath attack and limited access to your flight speed, but not your natural weapons. 

When in dragon form you have full use of your flight speed, breath attack, natural weapons, and any armor you were wearing as a humanoid is incorporated into your hide as thickening scales. You cannot make use of humanoid weapons while in dragon form.

This transformation into a humanoid counts as a 5th level Polymorph spell/effect. The following list applies:

• This does not require your concentration.
• This can be dispelled.
• You retain your statistics and hit points between forms.
• You can be polymorphed as per usual on top of your shape change. Changing forms while under the effects of an external polymorph does not cancel the external polymorph.
• Being rendered unconscious does not break the polymorph. Dying does.

While in humanoid form and not wearing heavy armor, you can exchange your remaining walk speed for flight speed. If you're airborne at the end of your turn you fall back to the ground landing on your feet. This does not negate fall damage, but you can deduct 20 ft of distance from the calculation. Once you use this burst of flight, you can’t use it again until you move 0 feet on one of your turns.

You can replace an attack as part of your attack 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 Dexterity saving throw. The DC for this saving throw equals 8 + your Constitution modifier + your proficiency bonus. A creature takes 2d10 damage on a failed save, and half as much damage on a successful one. The damage increases to 4d10 at 5th level, 6d10 at 11th level, and 8d10 at 17th level. After you use your breath weapon, roll a d6 at the start of each of your turns. You regain the use of your breath weapon on a roll of 5 or 6 on the die.

Dragon's in their true form are unable to wield weapons, they have natural weapons of their own. As an action you can attack with either your claw or bite attack. Beginning at 11th level, if you have the extra attack feature you may use your action to perform a multiattack, making one claw and one bite attack. The damage of your natural weapons increase at 5th, 11th, and 17th level, as shown on the table below.

You have resistance to the damage type associated with your draconic ancestry.

You can speak, read, and write Common and Draconic. Draconic is thought to be one of the oldest languages and is often used in the study of magic. The language sounds harsh to most other creatures and includes numerous hard consonants and sibilants.