@TheColorfulGirl,
There are at least two good ways to have sex without getting pregnant.
One is an IUD. These are inserted by a doctor or other medical professional, and they are very effective at preventing pregnancy. Another is birth control pills. They also work very well as long as you follow the instructions. If you aren't good at following instructions every day without making a mistake... birth control pills aren't as effective.
Condoms are important to prevent STDs, but they aren't the best birth control method if you really don't want to get pregnant.
And having a boyfriend doesn't mean getting pregnant is a good idea. Boyfriend's aren't permanent.
So use good birth control. For the record, I am not a doctor. It might be a good idea to talk to a doctor. He or she will be able to give you good medical advice on what is most appropriate for your life circumstances.