We want Marinette Dupan-Cheng to become an official Disney Princess. We feel like she has the requirements to become one such as...

The character must be human, or human-like in the cases of Ariel and formerly Tinker Bell. Marinette is fully human.
The character should not have been introduced into a sequel. If you made it a movie it would not be a sequel. 
The character should be born royal, married royal, or has performed an act of heroism in cases of Mulan. Marinette saves Paris every day.
The character's film should be a box office success that is neither underwhelming nor overwhelming, and/or have a cultural impact, like solely with the case of Aurora. This explains the absence of Eilonwy, Kida, Anna, and Elsa. She is clear here.
Along with it, the character must have massive appeal and recognition towards viewers and audiences alike. She is a clutz, she has many human characteristics, also she has a crush and that is the most human of any Disney princess.  

In the 2016 film Moana, Maui states that princesses have animal sidekicks. This has been evidently shown to be a common characteristic among the official members. But it is unknown if it is considered an official Disney Princess rule. If it is an officail rule than she has Tikki.

This is why Marinette Dupan-Cheng should become an official Disney Princess.