Self-possessed

Adjective

 * 1) in full control of one's faculties, and having a firm belief in one's abilities; confident, assured and poised

Thesaurus
aloof, assured, balanced, calm, collected, composed, confident, controlled, cool, detached, dignified, easy, easygoing, equanimous, equilibrious, even-tempered, firm-minded, forward, imperturbable, importunate, independent, levelheaded, peaceful, placid, poised, pushy, recollected, refined, reserved, self-asserting, self-assertive, self-assured, self-confident, self-contained, self-controlled, self-expressive, self-restrained, serene, strong-minded, strong-willed, together, tranquil, undisturbed, unflappable, unperturbed, unruffled, well-balanced