When you create a classic game, there are two possibilities: either it starts when you create it or it starts when another user does. If the first to create the game was your opponent, they'll be the ones to play the first round and they will have the possibility to win characters during that first round.
In any case, no user will be able to win more than three characters during the first round so that it is fair for both players.
Keep in mind that you will also be able to steal characters from your opponent during the game, we invite you to visit the article: How to steal characters from your opponent? so that you can be aware of the steps to do so.