Character Analysis
Think of Young Ju as a character with two identities: the rebellious, spunky teenager and the demure, goody-two-shoes. We mostly see the demure, goody-two-shoes side (because she really is a good kid), but it's hard to stay demure when you've got a dad who's as mean and brutal as Apa.
The Perfect Daughter
But demure she stays for most of her childhood. Take this moment for example: Young Ju's doing exactly what her dad is asking her to do—soaping down the car so that he can wash it off. Meanwhile, her little brother is standing in broad daylight, pants off, peeing into the street.
You'd think Apa would tell Joon to take it inside, but nope, he buys into the whole boys-will-be-boys mentality. This is understandably upsetting to Young Ju—why is she held to a higher standard of behavior just because she's a girl? She "[doesn't] understand why Apa thinks boys and girls cannot be treated the same. Why they are so different" (13.42).
Young Ju's sense of injustice, though, doesn't make her do anything. She
imagine[s] throwing [her] sponge into the air. Running fast, fast down the street. So fast that [she] begin[s] to fly. Away. From here. From [herself]. But when [she] open[s] [her] eyes, [she is] still standing in [her] place next to Apa. [She] turn[s] [her] head so [she does] not have to watch him spray down the car and make the bubbles disappear. (13.47-48)
It's the same kind of paralysis she feels when she hears her father beating Uhmma up:
Stop it, I say to myself. Go out there and stop it. But I do nothing. Say nothing. Only listen to the walls like a shameful mouse. (21.10)
And when she witnesses all the bruises her father has given her mother, her impulse tells her to do something, but—ever the dutiful daughter—she does exactly what her mother asks of her:
Do not speak of this to anyone, Uhmma says. Not even Gomo. Now go to sleep. I walk back to my bedroom. (21.26-27)
Let's just add, too, that Young Ju really is the "good older Uhn-nee" (10.42), responsible for Joon even when he's acting like a jerk. She bugs him about going to school when he's clearly not motivated to do so and basically calls her a nerdy loner; and she sympathizes with and helps him clean up his Legos after Apa beats him up even though Joon slaps her for accidentally breaking a Lego piece.
Rebel With A Cause
But like all good heroines, Young Ju needs to—and as such must—go through a major change. And as is the case with so many teens, it all starts with her BFF Amanda. Apa forbids Young Ju to see Amanda because he thinks Amanda is "worthless" and that Young Ju is "becoming too American" as a result (23.79).
Calling Amanda "worthless" seems to light a small fire under Young Ju because she actually says—out loud (albeit "quietly")—"No... She is not" (23.80).
Of course, Apa responds by hitting her (what do we expect, right?), but it's almost like Young Ju's found the strength in her character—and it's not long before she's giving Uhmma the tough-girl talk about Apa:
I stand up. Stare straight at Uhmma. You have choices, Uhmma. (26.66)
Pretty tough girl, isn't she?
Note the trend, too: all this toughness comes when she sees Apa treating others unfairly (to put it mildly). When Apa beats her, she just tries to survive the beating by zoning out so that "the world cannot touch me" (28.31), but other people? Not on Young Ju's watch, especially when it comes to Uhmma.
Not that it's easy—after all, Young Ju doesn't defend Uhmma until the very end. But when she does, it's a huge deal. It only takes one moment to create a long ripple of change in the Park family household… particularly when you get the cops involved.
Family First
Are you wondering why it takes Young Ju years before she calls the cops on her dad? The easy answer to that question is that it's because it's her dad. Even he has a few redeeming points about him, which is something Uhmma keeps reminding Young Ju about all the way until the very end of the book—even after Apa's out of the picture.
He's the one, after all, who teaches Uhmma how to brave the waves in the beginning of the book. A "different man back then" (30.49), Apa is similar to Young Ju because they are both "dreamers" (30.49). The only difference is that he doesn't know how to handle life when he can't follow through on the pursuit of his dreams, but Young Ju can and does.
But the harder answer is the fact of the family. Young Ju is trained to believe in the family as a unit, which is why Uhmma stresses that Young Ju comes from a "family of dreamers." It's a strong reminder that despite all of their problems, the Parks are where Young Ju comes from and she can't and shouldn't forget that.
Which is why Uhmma tells Young Ju to take the picture of her, Uhmma, and Apa to college with her. Sure she says it can help Young Ju "remember how to be brave" (30.51), but it's also a way to get Young Ju to remember her whole family, including her abusive father. Just like you can't be selective with history in general, you can't be selective with family either.
Another factor in why it takes so long for Young Ju to call the cops is that it's really hard to go against your fears, and if your fears tell you not to cross your violent father, we're pretty sure you'd listen too for a while. It's the same kind of fear that keeps Uhmma from believing she can make it on her own, and it's the fear that keeps Young Ju thinking she's a "shameful mouse," too weak to stand up to her father.
Here's another way to think about the question. Instead of wondering why it takes Young Ju so long to get the police involved, perhaps it makes better sense to wonder how she finally finds the courage to do so. Because for a girl taught to respect the family and be responsible to them, Young Ju does a really major thing when she turns her father in to the authorities. She fractures all that she's been taught about family in order to preserve what's left of the family (Uhmma, herself, and Joon Ho).
We don't know about you, but that seems like a pretty significant change in character to us.
Young Ju Park's Timeline