Legal Question in Criminal Law in California

Your question isn't clear. If this happened within California, then it doesn't matter under state law whether the minor was from another state. (There are potential issues under federal law, but your question is specifically about the law of California.) If it happened in another state, then that state's laws are the ones which apply to it.

If you're asking how California will treat a conviction from another state, the answer is that it will recognize the conviction. If someone convicted of such a crime in another state has moved to California he will probably have to register as a sex offender, but that will depend on specifics.