Garrett usually chooses to receive, but I would always defer.
For one, I love being able to strategize at the end of the first half knowing that I'm going to get the ball first in the third quarter with a chance to score twice without the other team having a chance to score. Back-to-back scores can dramatically change the game.
Second, the later in the game it is, the more you know and the better informed your decision making will be for your limited number of possessions. For example, in the first quarter, if you're facing fourth-and-1 from midfield, you might punt and give up one of your possessions. Later in the game, if you KNOW you need touchdowns or at least a field goal, you're more likely to go for it. Or if you're way ahead, you're less likely to take an unnecessary risk.
Third, by kicking off to start, you're most likely giving the opponent the ball inside their 30. If you receive and have to punt early, you'll most likely already be behind in the field-position battle.
And finally, the first quarter is historically Romo's worst quarter. This season, it's only his second worst (the second quarter has been his worst), but for his career, his first-quarter rating is just 80.9. In every other quarter, including overtime, it's at least 99.0. I'd rather give him the ball later in the game than on the opening possession.