She's 24. As for her personality...she's free-spirited, charming, spiritual, and goal-oriented. She comes across as more self-assured than she is. She's the calmest person in my family. She's also got a very dry delivery when she's joking, so people sometimes aren't sure how serious she's being. She's interested in traveling and making plans for the future. She used to spend a lot of time with friends, but she's become more of a homebody as of late. She prefers the countryside to the city, and she likes to be in nature. Not sure if that helps.
The one she's got is
this one from
Her Tongue.
Plays are well outside my area, and the only ones I'm familiar with had predominantly male roles. So if you have any tips, that'd be supercool.
As a disclaimer, I'm just going to say that the plays I'm about to recommend are plays I know about because I used them for monologues or acted in them myself, which means that I can try to recommend roles within those plays that might fit her personality, but ultimately I'm exposed to them because they fit my personality. We're in a similar age range and we're the same gender though, so at least there's that.
1)
The Secret Rapture by David Hare
Here's a summary I pulled from Wikipedia because it's easy.
Estranged sisters Isobel and Marion are forced to reunite when their father dies and they must decide how to handle Katherine, their young, alcoholic, mentally unstable stepmother who has been left nothing but the rural home in which they were raised. Isobel and her lover Irwin own a small graphic design company that is struggling to stay afloat. Her sister suggests she and her born-again Christian husband Tom help them expand the business by finding investors and making Katherine a partner responsible for finding new business. Isobel has grave misgivings about the plan, but finally agrees to it when Marion convinces Irwin of its potential success. Before long, the strain of running the expanded business causes a deterioration in Isobel's relationship with Irwin, who is becoming increasingly dependent upon her, while at the same time Katherine's tenuous hold on sanity begins to unravel.
She sounds like she'd make a good Marion, but Isobel is a possibility for her as well.
2)
A Lie of the Mind by Sam Shepard
Told in three acts set in snowy Montana, the story alternates between two families after a severe incident of spousal abuse leaves all their lives altered until the final collision at an isolated cabin. The two families, one composed of Baylor, Meg, Beth, and Mike, the other composed of Lorraine, Sally, Frankie, and Jake are connected by the marriage of Jake and Beth, whose beating and subsequent hospitalization at the hands of Jake initiates the beginning of the play. Exploring family dysfunction and the nature of love, the play follows Jake as he searches for meaning after Beth, and her family, as they struggle with Beth's brain damage.
I would recommend either Sally or Beth for her. I've used Sally for a monolgue and played Beth. Beth might be more interesting for your sister, especially if she's looking for a large contrast to her first monologue.
3)
The Pillowman by Martin McDonagh
There are no female characters in this play, but I've played Katurian and any role in this play could essentially be genderswapped. My Michal was also female. This play is extremely violent and might not be your sister's taste. I'll give you the Wiki summary anyway though.
Katurian, a writer of short stories which often depict violence against children, has been arrested by two detectives, Ariel and Tupolski, because some of his stories resemble recent child murders. When he hears that his brother Michal has confessed to the murders and implicated Katurian, he resigns himself to his execution but attempts to save his stories from destruction. The play includes both narrations and reenactments of several of Katurian's stories, most notably the autobiographical "The Writer and the Writer's Brother", which tells how Katurian developed his disturbed imagination by hearing the sounds of Michal being tortured by their parents.
4)
Scab by Sheila Callaghan
Anima's sphere of desperation and self-destruction is invaded by the arrival of her perky new roommate, Christa. Moved by a particularly malevolent statue of the Virgin Mary and a houseplant named Susan, Anima and Christa soon enter into a profound and intimate friendship that incurs traumatic results.
Consider Christa or Anima.
Also consider
Far Away and
Top Girls, both by Caryl Churchill. These are great plays with lots of interesting female characters.
If she doesn't like any of these let me know and I'll recommend some more. Tell your sister to break a leg!