Surprise birthday

Dear John,
                 I’m contacting you because of a party. Chris’s birthday is next wednesday, she will be 50 and she wouldn’t celebrate anything. I am planing to do her a surprise birthday. I also thought to make it with Alex, we are her best friends. My idea was making this celebration in her aunt’s house, it has an enourmous park to play football and a very big pool to play.
I’m looking forward to your answer, Juan Pablo