D&D 5E - Stats and CR for a very young gold dragon?

Circle Forms: ... Starting at 6th level, you can transform into a beast with a challenge rating as high as your druid level divided by 3, rounded down.

If the goal is to give this to her at level 6 instead of gold dragon, a bronze dragon would be more on par with the balanced challenge rating.

If you were to go with bronze instead of gold, for an in-between form I would take the Young Bronze Dragon, make the bit and claw only 1d10+5 and 1d6+5 respectively. Also lower the breath weapon do deal 6d10 damage, and reduce the HP down to an average of about 90. This should take things down to a more reasonable level.

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