In short, "she/they" is the most common way for a person to indicate that they go by "she/her" or "they/them" pronouns, likely with a preference for the former. It is not incorrect. Note: While "she/they" is commonly used by feminine-leaning non-binary people, a great deal of women (both cis and trans) also go by it.
Is it correct to say your pronouns are "she/they" or should it be "she ...
The difference is that she's and similar shortened forms are used in colloquial speech, but not in certain cases. In your example, she is being emphasised.
When to use "she's"(short form) and and "she is"(full form)? What is ...
Taken from the Free Online Dictionary: Usage Note: Using she as a generic or gender-neutral singular pronoun is more common than might be expected, given the continuing debate regarding the parallel use of he. In a 1989 article from the Los Angeles Times, for instance, writer Dan Sullivan notes, "What's wrong with reinventing the wheel?
word usage - Reason for the current trend to use «she» as the gender ...
It is not needed because the questions could be more concisely put as " Where is she/he?". This redundancy, and the efforts of seventeenth and eighteenth century grammarians to align English with Latin, lead some people to say it is ungrammatical to end with " at ".
Where is she? or Where is she at? - English Language & Usage Stack Exchange
Yes, both (s)he and he/she are acceptable abbreviations for usage where space is at a premium and gender of a person is important. s/he is not a common abbreviation, and will confuse more users than the other two.