Yes, I think it was. Queen and countess immediately became very close. But Gabrielle was a simple person, and she soon said to Antoinette that she did not want to go on in the court, and that she prefered to leave her before she felt to attached to her. Then, Marie-Antoinette burst into tears, and begged Gabrielle to stay with her. So, countess de Polignac accepted, by affection for the queen.
Maybe, for her tranquillity, it would have been better to refuse... But she loved Marie-Antoinette too much to hurt her.
Some people hating madame de Polignac gave a detestable explanation of this scene. They say that Vaudreuil and other ambitious courtiers sent madame de Polignac as a pilote fish to catch Marie-Antoinette, and that this was nothing but comedy. Well... in this case, how could this comedy last for years ? For their friendship lasted from 1775 to 1789... and even later, till 1793, since Gabrielle died thinking of her beloved friend.