Tic-tac-toe has been solved. The optimal first move is to go in the corner. As always, there is a relevant xkcd.

The first player can't guarantee a win, and the second player can't guarantee a win either. This is assuming both players make no mistakes in their moves. Therefore, neither going first nor going second guarantees a win if both players are playing their best. Tic-Tac-Toe is a solved  game.