Homebrew class that needs A-LOT of help (2014)

Hey! Just an FYI if you didn't read the title fully this is for 2014

 This idea came from a book that I really love.

A human that is able to turn into a dragon. The age of the dragon depends on the level of the character but the first few times they change they have to roll a con save DC 13 to see if they try to eat their party if they succeed 5-10 times in a row depending on the age of the dragon, if they succeed the save the required amount of times they don't need to make the save when they transform. If they do not transform for 8 days, if they try to transform they have to make a strangth save depending on the age of the dragon (DM's choice) If they fail they can no longer transform into a dragon for 13 days (If they fail the strength save 3 times they can never change into a dragon again) after that they have to make a strength check DC 14 to be able transform into a dragon again 

If you have any ways to improve this please feel free to let me know.

P.S. I would love if this is not full of criticism but instead helpful stuff for making this class better so that it is playable and not to over powered.

Basically, what you need to do is nix all of the mechanics you've laid out here, because none of them are fun. Transforming into a dragon should be something that they can just do, without lethal consequences, and you should make a stat block for the class to use. Base dragon stat blocks are far too powerful for a player to use.

Thanks for the help if you have any Ideas to further better this character please feel free to share

I'd suggest you take the Bloodhunter Order of the Lycanthrope subclass as a starting place and build from there, maybe mixing in some mechanics from Ranger-Drakewarden. There are also some feats in Fizban's for dragon-type specific abilities you might want to borrow. In general any mechanic that causes you to attack your own party is a bad idea, and will get you kicked out of the game in short order.

Thank you so much for the advice and I will take that into consideration