Shape-shifter's skin

As a changeling, your cellular make-up has offered some unique traits to utilize alongside your skills. You gain the following benefits:

• Increase your Strength, Constitution, or Charisma score by 1, to a maximum of 20.
• Your body manifests natural defenses. While you aren’t wearing armor, you can calculate your AC as 13 + your Dexterity modifier. You can use a shield and still gain this benefit.
• You have advantage on deception rolls when trying to hide your true nature.
• You gain proficiency in your choice of changeling instinct skills.