Thad: There is no general answer for that, it depends on the rolls. The general principle is that doubles being a great roll, you want to focus on offense. This is because the positions where both players anchor high are mostly about equal, while prime against prime positions are not.
But tactics often overrule that principle. 3-3 is one of the most difficult rolls. The 3 is not a great point, but making it unloads the stack on the 6. The 5 is great, but making it abandons the 8. The 10 is not great, but it unstacks the midpoint. The defensive 20 is great, but you would like to focus on attack.
After an opening 6-1, the value of advancing the back checkers goes up, so I like your move. At www.bgonline.org there are all rollouts for all second moves that are considered non-trivial, and 24/21(2) 13/10(2) indeed rates as the best move.