The sentence which indicates that Mariah is not yet ready to publicize her friendship withh Jordyn is the following:
Less pleasant was the part where some of Jordyn's "crew", as she called them, showed up and seemed standoffish with me, like they wished I weren't there.
This sentence shows that Mariah felt uncomfortable in front of Jordyn's friends and in this way she realized that she wasn't ready to let people know about her friendship with Jordyn yet. Publicizing their friendship was unexpected and unplanned as Jordyn's friends appeared uninvited and this situation made Mariah feel unwanted.