you are immune to fire damage. your natural armor gives you an AC of 17. you may choose an additional saving throw proficiency, in either Dexterity, Constitution, Wisdom, or Charisma saving throws 

you have blindsight out to 10ft and darkvision out to 60ft

You breathe fire in a 15 ft. cone.  Creatures within the area take 2d6 fire damage.  The amount of fire damage increases to 3d6 when you reach 3rd level, 4d6 when you reach 5th level, 5d6 when you reach 7th level, 6d6 at 9th level, and 7d6 at 11th. Creatures may succeed on a dexterity save, with a DC equal to 8 plus your proficiency bonus plus your Wisdom modifier, to take only half damage. you have a number of uses that that is 2, plus your proficiency, uses that reset on a long rest.

Your bite is a natural weapon with which you are proficient. Your bite deals 1d10 plus your strength modifier piercing damage, plus 1d4 fire damage

Your creature type is Dragon, rather than humanoid.  You cannot wear armor, nor wield weapons or shields.

Regular folks fear and hate black dragons.  In civilized areas, regular folk are all initially hostile to you, and guards will attack you on sight, unless they have a good reason not to.

Your Strength score increases by 2, and your Charisma score increases by 1.

Dragonborn are taller and heavier than humans, standing well over 6 feet tall and averaging almost 250 pounds. Your size is Medium.

Your base walking speed is 30 feet, a climb speed of 30 feet, and a flying speed of 60ft

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.