To answer simply, no your body temperature does not cause nor prevent pregnancy. Body temperature can be an indication of a woman's fertile period each month but it is an unreliable indicator. Most woman will see a slight increase in their body temperature just prior to or during ovulation. The increase in temperature does not directly effect pregnancy. It is simply a possible indication of increased fertility. Checking the body's basil temperature is typically done by those trying to conceive. It is not accurate nor precise enough to be considered a viable way to prevent pregnancy. Other changes in temperature such as fever or weather patterns will not effect a woman's ability to conceive a child. Many women conceive during the summer months. The changes in the weather certainly do not effect the woman's ability to become pregnant. By the end of the first trimester, a pregnant woman can start to feel more heated than normal or warmer than those around her. She has more blood, hormones, and other body changes that cause her to feel hot even in cool temperature. Some woman will avoid becoming pregnant in the summer for the comfort of the mother, but this does not mean they cannot become pregnant due to the increased temperatures.
Women between the ages of puberty and menopause can get pregnant no matter what their body temperature is and during any season of the year.The so-called "rhythm method" of birth control which uses temperature as a gauge of fertility is not particularly reliable, and unlike barrier methods of birth control offers no protection against sexually transmitted diseases.
If you are concerned about the possibility of becoming pregnant, you should consult your school nurse or family doctor for a discussion of various birth control options, Also, if you are engaging in any form of physical intimacy, you should make sure that you are fully protected against sexually transmitted diseases.
Make sure to consult a medical profession on these issues rather than relying on urban myth or peer group gossip.