Well, I haven’t seen Logan yet but the problem with the question is “realistic”. This is X-men, realism left the building ages ago. Nothing is realistic. If you’re asking about realism then you’re asking the wrong questions because superpowers change the rules. What you’re really asking is: should an eleven year old child be able to fight on the same level as an experienced warrior like Wolverine?
And the answer is, in the Marvel universe characters with healing factors (like Wolverine) have recovered from being burned into ash by the sun. So, in a setting where his healing factor is failing and he’s dying but she’s young, genetically/physically enhanced, and hers is working at full throttle then why not? She’s a tiny Logan. A rage-filled murder ball dedicated to death and destruction, created in a lab that turns human guinea pigs into ultimate weapons. So, I ask, why not? She’s doing exactly what she’s been designed to do, minus it being on the orders of someone else.
What stops children from competing with adults is three things.
1) Physical immaturity. Their bodies are still developing, and not on par with an adults.
2) Mental immaturity. Their brains are still developing, and don’t have the same basic understanding that adults do especially in regards to consequences. They don’t really grasp concepts like “death” and “gone forever” very well. Psychologically, these kids get pretty messed up.
3) Due to the above two problems, unless they have weapons, they can’t overcome the gap.
X-23 does all three. She has the healing factor, genetic enhancements, and blades coming out of her hands and front toe, all of which solve two of the above problems. They allow her to go toe to toe with adults because she can simply power or brute force her way through it. From a combat perspective, it doesn’t really matter if she gets hurt or go through serious body horror as her body will repair itself. So, someone without morals could put her through a meat grinder and still use her again. Plus, at least in X-men Evolution and the comics, she tends to be psychologically messed up. Someone who was treated as a weapon from the moment she was born, trained as a weapon, used as a weapon, and doesn’t really comprehend most “normal” human experiences. A clone with all Wolverine’s experiences, except she went through them as a child.
Laura Kinney, X-23 is by all standards a fairly new character in the Marvel universe. She was first introduced in the early 2000s through the WB cartoon X-Men: Evolution. Like Harely Quinn, she’s a canon immigrant. When she was introduced in the cartoon, she was a teenager.
In character, she was an angry violent rage-ball, a teenage version of Logan except more lost and unstable. However, the major difference between their experiences was that where Logan was an adult when he went through the Weapon X program, she was a child. She was the twenty-third test subject, and the only one who survived the experiments. X-23 was desperate to find out who she was and where she belonged; and, having been “raised” by Hydra, determined to find (and, possibly kill) Wolverine whom she viewed as responsible for everything that happened to her. That desire was mixed up in her desire to know who she was. Because she was a human weapon, she couldn’t distinguish between the two. Fighting was what she knew how to do, so that’s what she did. Her introduction was sneaking through the X-men mansion, disabling all the other mutant children and teachers in order to single Logan out to fight.
As a character, considering everything else, she was a fairly accurate representation of a child raised to be a human weapon. Psychologically traumatized, unstable, and unable to really comprehend her emotions or concepts like “friendship” and “family”. Deeply mistrustful of anyone and anything who got too close, unable to communicate her needs except through anger and violence. Any approach was likely to elicit an immediate, violent response.
She doesn’t know how to be anything except a weapon.
Logan could reach her because Logan understood what she’d been through, but he also couldn’t really help her and it took a long time before she came to trust him (if she ever really did). That door didn’t open often for anyone else.
If you want to see her first appearances then the episodes to watch are “X23″ and “Target X”.
The name “Laura Kinney” comes (I think) from the comics as she originally did not have any name other than X-23.
In the comics, she’s another of the Weapon X subjects and the 23 refers to her gender rather than the number of times it took to create her. She escapes like she does in the movie, and eventually starts trying to figure out who she is.
It’s not really worth asking questions about realism when a setting has explicitly ejected realism. Have a good guffaw over anyone trying to argue about the “realism of Batman”. There isn’t any. The setting has defined its own definition of realism and that’s what it follows. Realism isn’t everything, and it doesn’t define what a good story is. Often, it’s not even the question you should be asking. Avatar: the Las Airbender has some awesome fighting for a children’s cartoon, fighting clearly drawn (ha!) from martial arts in the real world. However, it is by no means realistic. And, honestly, that doesn’t matter.
Well-told stories are defined by how well they tell their stories, and maintain their suspension of disbelief. Everything else after that is popcorn. Realism comes into play when we admire how well someone has done their research, how well that research supports and enhances our experience when consuming media. You don’t want to understand combat just for an added dose of realism, but also because knowledge gives us more options to work with. The more you know, the more detail you can add. All the better to create a more enjoyable experience, my dear.
Understanding the rules is the first step in figuring out how to break them, or just manipulate them to your advantage. Whatever works.