Excel: IF statement with 3 possible outcomes (2 times text, 1 empty cell)

Situation:

Cell A1 is a number (age of a person)

Cell B1 generates one of 2 texts.

I can't get to the solution of this: If A1 is larger then 14 and smaler or equal to 17 it should give text A. If A1 is larger then then 17 it should give text B. But if A1 is empty B1 should stay empty too.

I messed my head already with this puzzle.