Technically you're just a spicy goblin, so you age just as they do. Goblins reach adulthood at age 8 and live up to 60 years.

Again, spicy goblin. Goblins are between 3 and 4 feet tall and weigh between 40 and 80 pounds. Your size is Small.

You can see in dim light within 60 feet of you as if it were bright light, and in darkness as if it were dim light. Your ties to the Elemental Plane of Fire make your darkvision unusual: everything you see in darkness is in a shade of red.

You have resistance to fire damage. What'd you expect from a spicy goblin?

You know the Control Flames cantrip. Once you reach 3rd level, you can cast the Hellish Rebuke spell once with this trait as a 1st-level spell, and you regain the ability to cast it this way when you finish a long rest. Constitution is your spellcasting ability for these spells.

You can take the Disengage or Hide action as a bonus action on each of your turns.

When you damage a creature with an attack or a spell and the creature’s size is larger than yours, you can cause the attack or spell to deal extra damage to the creature. The extra damage equals your level. Once you use this trait, you can’t use it again until you finish a short or long rest.

You can speak, read, and write Common, Infernal and Goblin.

Your fiery nature and your short stature makes you quick to panic. You have disadvantage on saving throws against gaining the frightened condition.

Choose an ability score to increase by 2, then an ability score to increase by 1.