Bipolar disorder is an issue that has a big influence on a person’s life. So if you realllllly want your MC to have BD,then don’t make it just a character trait,you know? Don’t just mention it somewhere during narration and forget about it. If MC’s case is untreated,then it should definitely play a part in the story (like how MC’s behavior differs depending on whether she’s manic or depressed,for example). If MC is fighting her disorder,then show it (like don’t show her partying and drinking when she’s supposed to be on meds).
And of course, don’t use BD only as an excuse for some sh*tty actions.
I would say that if after reading your story people want to take care of their mental health and feel encouraged to do so,then you did a good job 
Hopefully that helps a bit 