Any 14 year old should not be having sex at all. In individual needs to have a great deal of personal responablity before having sex. A 14 year old is still a child and needs to be a child. Concentrate on finishing school and making a future for yourself. At age 14 a person is not mentaly and emotionaly secure to have sex. Sex should be with a person that you care about a great deal. With the amount of STDs out there, you can screw up your life forever with just one STD.
In addition to the above most countries in the world do not consider 14 to be the legal age for giving consent for sexual activities. Anyone who has sex with a 14 year old or anyone younger is commiting statutory rape and will be charged with a child sex offence even if they are the same age as you or also under the age limit in your country. Whatever relationship you are in with someon you should not be having sex with them until you reach the legal age of consent and after that you should only have sex if YOU want to and only after checking if your partner has any STI's by asking them to have a test, never take their word for it, always ensure they are tested. But while you are 14, concentrate on school, games, tv and wasting time until you have to work hard, not sex.