No worries. Three weeks should not be too long too wait. The skin will not overgrow the sutures. The earliest that I like to take sutures out of the skin in the chest or torso area would be in the 2-3 week time range. You want to give the skin adequate time to get some strength to the repair, but not leave them so long that the skin develops unnecessary inflammation or leave permanent suture marks behind.
Usually the sutures are removed at 2-3 weeks post op depending on the healing achieved; every patient recovers differently.
So it is up to your surgeon to assess your progress and schedule your suture removal.
Best of wishes to you.