Question: I was writing the other day and I used the word "ubiquitous". 

While I don't think "ubiquitous" is the most egregious example of "Using Big Words To Sound Intelligent", and would be perfectly acceptable in most novels, it's just, my novel's demographic would be young teenagers, and I definitely did not know what ubiquitous meant when I was a young teenager.

Personally, when I come across an unknown word in a book, I have to take a minute to research what that word means, taking me away from the book.

On the other hand though, this could be seen as a teaching moment where I can teach young readers the meaning of new words

Answer: 
Don't use a big word when a singularly unloquacious and diminutive linguistic expression will satisfactorily accomplish the contemporary necessity.
Yes. But also, it depends on how young are your audiences. Search on appropriate words for the younger ones to understand.