One of the gifts of being young is that particular blend of self-confidence and self-consciousness. Jaden and Willow Smith have managed to turn this form of heady teenage introspection into expression instead of ennui. Willow, the 14-year-old musician whose debut single, “Whip My Hair,” went platinum when she was not yet a teenager, explains that the gift of life is “looking at nature and being, like, ‘Wow, I am so lucky to have a body and to breathe and to be able to look at this.’ ” To which her older brother Jaden, a 16-year-old actor and musician, adds: “And the huge, terrible thing the world would be missing by not expressing yourself.” To that end, both Jaden and Willow, the children of Jada Pinkett Smith and Will Smith, released new albums this month, including two tracks by Jaden that make their public debut here.