We should probably talk about Kara Young and how this woman can fit what feels like a mountain of blood, heart, sinew and febrile emotional response into a frame that can’t stretch past five feet.

Young (“Syncing Ink”) is now starring in “All the Natalie Portmans,” a top-heavy coming-of-age dramedy by C.A. Johnson at MCC Theater. She plays Keyonna, a queer teenager grappling with an alcoholic mother, a dead father, an overburdened older brother, a complicated crush and the threat of eviction. It’s too much, but somehow Young meets that too-muchness with a restless, vital performance, all busy hands and tight lips and twitching eyelids.

Could Natalie Portman do that?

Set in Washington in 2009, the play tracks a tumultuous few months in Keyonna’s life. A charter school student with a spotty attendance record and an obsession with white actresses, she shares a small apartment with her brother, Samuel (Joshua Boone), who works nights at a local bar, and her mother, Ovetta (Montego Glover), who cleans hotel rooms and occasionally disappears for days on end, sunk at the bottom of a bottle.

Keyonna soothes herself with collaged vision boards and ’90s movies, and dreams of writing screenplays for Natalie Portman, or someone like her. “Smart, but sweet,” Keyonna says. “And kinda sexy in an untouchable way. Like one part princess, one part stripper, one part Russian spy.” A woman cannot live on DVDs and dry cereal alone, but Keyonna gives it her best shot. When she needs extra comfort, she imagines a Portman character emerging — from the bedroom, through the front door or, chillingly, out of the fridge — just to hang or battle with lightsabers. This could suggest a dissociative disorder; Johnson treats it as a quirk.