She's not doing XC for XC... she's doing it because her "friend(s)" is on the team.
It was not really 'her' inclination to try out. It was yours...
For her, it is not about XC, it is about being where her friends are.
I used to do cross country in high school... but I LOVED it and was the top runner and the Coach recruited me. I used to run anyway, for personal fun. On my own. I then joined XC and did it for the love of the sport. Even if I had NO friends on the team, I would have still ran. In fact, I was not all 'chummy' with the girls on the team... I found them to be icky and so so sassy. Putting it nicely.
For your girl... she needs to do something that SHE likes and enjoys and has a passion for. Something that floats her boat. Otherwise, she will not enjoy it nor want to participate in it... consistently nor in a dedicated manner which is integral to any sport.
Have HER see what floats her boat.
What SHE likes.
What hobbies she'd like... to explore.
She has to "own" her own.... activities and participating in it will then follow.
Maybe, she can take classes on computer game designing... which she seems to like.
The thing is, a child... does not 'have to' be in any sports. They do not have to play a sport. There are SO many other activities... that a child or any person, can enjoy and participate in.... and which can help a person, socially.
all the best,
Susan