Does sex education make kids worse?

Hi! My sister is in grade 5 and she had sex education for at least 2 weeks now. She has been acting wierd after that and acting innaporpriate. I think that sex education should not be taught unti lthey are in grade 11 and 12 and onwards. Most of the time, kids are having sex and trying stuff out because they think it is cool to try out and it is not. I think that this problem NEEDS to be fixed NOW, What do I do with my sister now. She has been learning it and now interested in it and its in her head now. WHat do I do konw. Someone pleeeeeeessssssss help immediately.