Dragon Defiant by Viola Grace

Born nameless in a tank, they try and make her into a weapon, but she chooses defiance.

Eltrinia sounds like a good name, and Lem comes naturally. After falling through the sky during a lightning storm, Eltrinia is free of the tube that they grew her in, and while she doesn’t yet know her name, she knows that she needs to get in touch with society.
A fisherman and his wife take her in, and a shore patrolman offers to take her to safety, but minimal contact with him tells her all she needs to know. The valley wants her back, she is expensive, and they have scouts looking everywhere for her. Her captor thinks he is in charge, but that is when he meets the lightning.
After that, things get a little blurry.