It's very healthy for a young girl to be deterred from promiscuity by fear of contracting a painful, incurable disease, or cervical cancer, or sterility, or the likelihood of giving birth to a dead, blind, or brain damaged baby (even ten years later when she may be happily married).
Be warned against all 'good' advice because 'good' advice is necessarily 'safe' advice, and though it will undoubtedly follow a sane pattern, it will very likely lead one into total sterility--one of the crushing problems of our time.