Simplify the following text for a Grade 4 native English-speaking person.
Original: Anne 's mother , Sophie of Mecklenburg-G Ã 1\/4 strow , however , was only seventeen , and three years later did bear Frederick a son , the future Christian IV of Denmark .
Simplified: Anne 's mother , Sophie of Mecklenburg-G Ã 1\/4 strow , however , was only 17 . Three years later she did give birth to a son .