Yes, it's fine.
From the tournamet rules:
2.4 Conceding or Intentionally Drawing Games or Matches
If a game or match is not completed, players may concede or mutually agree to a
draw in that game or match. A match is considered complete once the
result slip is filled out or, if match slips are not being used, a
player leaves the table after game play is finished. Until that
point, either player may concede to or draw with the other, though if
the conceding player won a game in the match, the match must be
reported as 2-1. Intentional draws are always reported as 0-0-3.
Players may not agree to a concession or draw in exchange for any
reward or incentive. Doing so will be considered Bribery (see section
If a player refuses to play, it is assumed that he or she has conceded the match.
But remember that you can't use the sideboard if you decide to draw before starting to play:
2.3 Pregame Procedures
The following steps must be performed in a timely manner before each game begins:
- Players may exchange cards in their decks for cards in their sideboards. Players may only do this after the first or subsequent
game of the match and not for games that are restarted or games that
are drawn before any game actions are taken.
Matches are played until time has run out or until a player has won a certain number of games. Therefore drawing a game will not use up one of the games in the match, because there is no limit to the number of games that can be played in a match:
2.1 Match Structure
A Magic match consists of a series of games that are played until one side has won a set number of games, usually two.
Drawn games do not count toward this goal. If the round ends before a
player has won the required number of games, the winner of the match
is the player who has won the most games at that point. If both
players have equal game wins, the match is a draw.