Kenzie is a great name for her! It suits her, I thinks
I'm glad to hear she's settling in so well with the whole family! She sounds like such an easygoing little girl.
With regards to your question, at the moment, I think you should wait a few months at least before thinking of another bird. She sounds very social and outgoing and she clearly fits right in to her human flock. Generally if she were moody, antisocial, quiet, inactive, etc. then a same species companion would benefit her, but I think she's just fine on her own and it sounds like you're there enough to give her plenty of interaction time
I wanted to share my experience with you--
My girl, Mallorn, just turned three this year, and she's lived with me as a single budgie her whole life. She is bonded to me but enjoys the company of the whole family, and although I am not here all to day due to school/work/other things, I still am able to interact with her for several hours a day, by letting her out of her cage when I get home, and spending a good half hour just talking to her. She is a very happy little budgie and just thrives in this environment, and when the house is quiet in the late mornings to afternoon we leave on some classical music and she takes a few naps and has some time to herself. She loves her human flock and she doesn't mind at all that she's not a human (or, as it may be, that we're not budgies
) Of course, not all birds are like this and she's very flexible and we've developed a great routine, so I only say this because Kenzie sounds like she is very happy with you and your family
Introducing another bird could change her personality and the things she likes to do with you, too.
Also, it's best not to have a mirror in a solo budgie's cage--they can get overly attached or obsessed with their reflection and it can trigger moodiness, aggression, and in extreme cases, the females could even lay eggs
It's best to remove it and she'll have plenty of fun playing with you and her toys
I hope this helped
I look forward to hearing lots more about your gorgeous girl!