We can take our computation of the interval between two moments in time and combine it with the trick we developed for using the powers of mathematics to simplify multi-level comparisons to reduce the amount of work we impose upon the time/date engine.

static void PrintAge(DateTime bday, DateTime asof)
{
 // Accumulate years without going over.
 int years = asof.Year - bday.Year;
 if (asof.Month*32 + asof.Day < bday.Month*32 + bday.Day) years--;
 DateTime t = bday.AddYears(years);
 // Accumulate months without going over.
 int months = asof.Month - bday.Month;
 if (asof.Day < bday.Day) months--;
 months = (months + 12) % 12;
 t = t.AddMonths(months);
 // Days are constant-length, woo-hoo!
 int days = (asof - t).Days;
 SC.WriteLine("{0} years, {1} months, {2} days",
              years, months, days);
}

Observe that we avoided a call to the AddYears method (which is presumably rather complicated because years are variable-length) by replacing it with a multi-level comparison to determine whether the ending month/day falls later in the year than the starting month/day. Since no month has 32 days, a multiplier of 32 is enough to avoid an overflow of the day into the month field of the comparison key.