Well shoot, guess it sure is a good thing that if we don't give them condoms, there's no way they'll ever have that sex they aren't ready for!
In Germany, we've found a way around that: we consider it socially acceptable for young adults to bone. This solution has two major consequences:
1. It removes the stigma surrounding sex and sex ed, and ensures that people can have sex when they are ready with all the necessary tools
2. It makes teenagers a lot less obsessed with sex, because it lacks the extreme taboo it has in your culture, and is a lot less insane or risky to do.
Or, or, or you could avoid having to bind a shock collar around your children, trust their judgment for once, and accept that sex is a thing that happens and there's nothing inherently wrong with it if done safely, sanely, and consensually. This squeamishness towards sex, this treatment of something so fundamentally natural and human as though it was a huge taboo that we cannot encourage (or even prepare people for, despite knowing full well that it's going to happen and that not preparing them makes everything way worse), is a large part of the reason that sex and sexuality are so messed up in the USA.
Or, barring that, if you really insist, may I recommend a chastity belt? Absolutely no chance of premarital sex, and as an added bonus, masturbation is pretty difficult as well. It's pretty much the only thing that has a snowflake's chance of working, anyways.