Welcome to the forum! You did a very good job on the eagle ray and the precreasing, especially since you started just two weeks ago. I think the eagle ray had a difficult sink or something, but you navigated it very well. From what you have already done, I can definately say that you will be able to do some really complex stuff soon (Maybe even the ryu jin. Other folders have already folded it, and when you want to as well, I am sure they will give you some great advice). Welcome and good job so far!
P.S. It seems like you are attracted to harder models. My advice would be not to skip some of the simpler ones - they are nice as well, and might even help you to do harder models.
Regarding the Won Park koi, you have a decent start on the precreasing.
I might warn you though, that the koi, as well as most of the advanced, complex models, oftentimes have a couple, or several, difficult tricky moves. These are generally overcome by intuition, experience, trial & error, and perception gained from past foldings.
Most diagrams are frequently deficit of some steps, leading to potential frustration.
Hence, some considerable practice folding from Lang ( Origami Sea Life , Origami Zoo and Origami design Secrets), Seiji Nishikawa (Works of ), Jun Maekawa ( Genuine Origami), and Nicolas Terry's books will give you some valuable experience .
Otherwise, it's kinda like starting out with Sipho Mobana's Baby Fugu, a daunting exercise.
Best of luck !
May I wish success to all who cope with the mountains & valleys of Life,
with all its peaks & depths, as well as Origami .