So I think I figured it out.
The one thing that is confusing me for so long is that Cream Soda is not considered an "adult" but at the same time she's heavily implied to be a college student especially with the new information that they live in dormitories at the RCA.
So if Cream Soda, Cherry Cola, and Blue Mallow are not considered adults yet they are in a school that's heavily implied to be a college then what the fuck are they?
And then it hit me late at night...
They are in their late teens.
This happens when recalling all the other cookies who have similar age discourses until I remember Candy Apple. Her va said that she was told but she should voice her around the age of 17-19, a late teen, and even though I don't think Candy Apple sounds like that, I do believe Cream Soda does.
So late teens as an age group is a possibility and that actually may be the answer to this whole discourse.
That can explain everything, because, keep in mind, the legal age of being an adult is 18 in a lot of places, but just because you're legally an adult doesn't mean you have the mind of one.
This could explain why she was able to attend the sun tournament when everyone is a bunch of adults.
That's why she's able to attend a school that's very much so a college because first years are usually around that age.
That's why Tangerine Tanghulu considered her to be a "grown up"
That's why Lemon Zest says never once call her a "kid" despite many other cookies calling her the same thing because she is likely around the same age as him. Lemon Zest is likely to be a young adult himself or at least that's what the fandom agrees. (If I am wrong please do inform me)
That's why they're considered not adults, yet they are in a college environment.
And I know some people are wondering how I come to the conclusion that RCA is a college, let me provide my reasonings
1. You can learn anything at the school like a college.
2. They attended a preparatory school and the whole point of prep school is to prepare you for college even though I found that that definition weird because don't all schools do that? but it's something to at least note
3. The entrance exams I'm pretty sure we're all familiar with stuff like SATs and ACTs that are entrance exams. (Fun fact - there are like 13 types of entrance exams)
4. The RCA has dormitories, something that colleges and universities are known to have
So now we come to the answer or whether or not she's considered a minor or an adult.
The answer is technically both, and I hate it.
I blame Devsisters for making things so complicated and also never explaining the education system in the franchise. I'm honestly starting to believe that they're allergic to confirming their character's ages.
It took almost 2 years worth of dissecting every single piece of evidence that could allude to her age, we finally have an answer.
Even though we do have an answer, it won't change the fact that this whole age discourse will still be going on because people will be arguing on whether or not we should interpret her as a minor or an adult.