In the story in First Meetings, Investment Counselor, it is stated that Ender has just turned 20. However, on page 292 of the 1991 edition of Ender's Game, it says that he is 11. Then, he goes to a colony, which takes two years (pg 311). After that, it says he was with an 11 year old boy who was three when the colony was founded. So the ender has been on the colony for 8 years. 11+2+8=21 years old, hundreds of years before he was supposed to be 20. Impossible, even factoring in relativity.