This is nothing more than a blackmail scam, which we have heard many times on this site. Here's how the scam works:
You think you're communicating with someone of age and then you learn the person is a minor when you get a call from a so-called irate parent who asks you for money.
We actually see this situation fairly often because there are predators who hang out in chat rooms and on dating sites, just to set people up for extortion. But you can't give in to blackmailers. If you do, the money fo so-called car repairs will only be the first installment, and you'll be paying off these thieves for the rest of your life.
Blackmail is a crime, and you don't want to allow anyone the power to control your whole life. Do not send any money. Cease all contact with these people and block them so that they can have no further contact with you. They are only trying to extort money from you and when they won't be able to manipulate you, they will likely move on to someone else they can intimidate. You never met or had sex with this person, so the idea that you could be charged with statutory rape is pretty preposterous.
In all the time we have seen this "Sextortion scam" we have never been informed by even one customer that the threat was carried out. To feel more safe, however, you can go talk to a local criminal lawyer. Let him or her see the texts you shared, because if it's favorable to your position, you can be proactive and report THEM to the police for fraud and extortion.