Two days later her older twin brother, Terry, celebrated his birthday.

How can this be, assuming that the difference in twins' ages can be a few minutes, but not over an hour?

There are at least three possibilities:

• Kerry and Terry might not be the twins. Terry might be just one of Kerry's older brothers who are themselves twins;
• Terry could have been born on February 28th and Kerry on the 29th on opposite sides of the International Date Line and celebrate their birthdays where officially and legally one born on February 29th celebrates it on March 1st on non-leapyears (and in some locales even during leapyears); or
• Terry could have been born on February 28th, and Kerry on March 1st on opposite sides of the International Date Line and it is a leapyear in which they celebrated.