This article is from the All My Children FAQ, by Margaret Gibbs gibbsm@no_spam.poppyware.com with numerous contributions by others.
As of 1993, she is 23. The actress is about 16, though.
When Kendall first appeared on the show, she was depicted as a
teenage runaway. Once it was revealed that she was Erica's
daughter, there was a large outcry from the fans, due to major
continuity errors. If Kendall was, say 16, and Erica was 16,
or 15, or 14 when she was raped (TPTB keep changing this one too,
but I think they've finally settled on 14), then Erica would
only have been 30. Since the show has been on for over 20 years,
and Erica was a teen when the show started, the math is just
too much to overlook. So, TPTB "aged" Kendall overnight, and
suddenly there were many references to the fact that she was 23,
old enough to drink, etc. They started dressing her older and
changed her makeup. It is hard to suspend disbelief enough to
make a 15-year-old girl be 23, but it is easier than believing
that 44/45-year-old Susan Lucci is 30.
Update: On April 14, 1995, Sarah Michelle Gellar, who plays
Kendall, turned 18. Susan Lucci will be 47 on December 23, 1995.