less ifs if you use the variable
#define swap(a,b) do { int c = (a); (a) = (b); (b) = (c);} while(0)
if (age[2] > age[1]) swap(age[2], age[1]);
if (age[1] > age[0]) swap(age[1], age[0]);
if (age[2] > age[1]) swap(age[2], age[1]);
or
if (age2 > age1) swap(age2, age1);
if (age1 > age0) swap(age1, age0);
if (age2 > age1) swap(age2, age1);