HPV causes cervix ca. Starting sex early increases likelihood of multiple sex partners, which increase risk of acquiring hpv (human papilloma virus) which in turn increases risk of cervical cancer.
Related. If a girl starts having sex at a young age, and has multiple sex partners, it increases her risk of cervical cancer.
Maybe. Cervical cancer is caused by hpv (or "venereal warts"). The virus is spread through sexual contact - so it is an std. If you have unprotected (without a good condom) sex then you may be exposing yourself to hpv and, therefore, increasing your risk of cervical cancer in your lifetime. You are also exposing yourself to hiv, hepatitis, chlamydia, gonorrhea, and other nasty diseases. Use a condom.