What's the Scenario: Is age really nothing but a number?

A listener met this woman on a holiday last year  October. There was nothing on that tour besides we got on well. He can’t remember the reason but there was a message about two days after we got to our respective homes. 
Since than they have a call in the evening everyday, chatting about how the day went over politics to how family is. She is coming for 3 month to Cape Town. 
The PROBLEM she is 30years his junior. 
She knows his age as they celebrated both their birthdays on the holiday last year. 
As much as he likes her, something feels off.
Is age really just a number??