Indeed Olympic football rules are different for men and women tournament and preliminary (qualifying) and final (Olympics) competitions:
All players participating in the preliminary and final competitions of the Tournament shall be born on or after 1 January 1989.
However, a maximum of three male players who do not meet this age limit may also be included in the official list of players for the finals competition.
There are no age restrictions for the players participating in the women’s Tournament.
Please note that the men over 23 can only play at the Olympic finals, not the preliminary or qualifying rounds.
Since 1992 male competitors must be under 23 years old, with three over-23 players allowed per squad. The new format allows teams from around the world to compete equally, and African countries have taken particular advantage of this, with Nigeria and Cameroon winning in 1996 and 2000 respectively.