You are humanoid.

You are Medium 

Your walking speed is 35 feet. 

If you see unsecured flames within 25 ft of you, you must roll a DC 15 wisdom saving throw or become frightened. You dont have a fire vunrability, just a fear. 

As an action, you can change your form into your true form, a wolf, though none of your game statistics change. You are still yourself, you can control yourself, you dont go into a murderous frenzy. Your wolf form is slightly bigger than a great dane dog. Unlike cursed werewolves, born werewolves dont have an inbetween/hybrid form, just the two forms (full humanoid and full wolf) 

You stay in the new form until you use an action to revert. You always revert to wolf form upon death or unconsciousness.

Your tough skin grants you resistance to bludgeoning damage

In your true form, you can use your claws and teeth to make a claw attack (1d4 slashing) or a bite attack (1d6 peircing) 

Once per long rest you may use a reaction to reroll a 1 on a STR/DEX based skill check (not an attack) 

Born werewolves are immortal and stop ageing at 25.

They can still be killed though. 

During a full moon you gain a +2 to all STR/DEX skills you are proficient in but also gain a -3 to all INT skills you are not proficient in. This effect lasts until sunrise

During a dark moon/new moon (same thing but different names) you gain a -1 to all skills you are not proficient in. This effect lasts until sunrise

Your enhanced senses give you advantage on any checks that use scent or hearing.

You also gain disadvantige on any saving throws to do with scent or noise (for example, a saving throw to avoid the deafened condidtion, or a con saving throw to do with scent. )