Don't confuse
实足 ('the full/exact amount') with
十足 (shízú, 'one hundred percent, fully' — same pinyin, different characters).
实足三十岁 = 'a full thirty years old (exactly that age)';
信心十足 = 'full of confidence.'
实足岁 specifically means age counted in completed years (Western reckoning), as opposed to
虚岁 (the traditional Chinese 'nominal age' that counts the year of birth as one).
