If you're nervous go with big brand names, because they need to worry about lawsuits from the condoms breaking! (just kidding). Make sure it's put on properly. It's easy to put them on inside out which will increase the chances of breaking. Since this is your first time, I know it sounds lame, but read the instructions and put it on yourself. Since this is your first time, the boy won't have anything to lose if the condom breaks so take responsibility. But condoms don't break frequently. Just make sure that you're not using this as a way to put your fear of losing your virginity to something else, so it sounds like an excuse. The best excuse not to have sex is, I don't want to. Also, if you use lubricant, use a condom-safe one. Some oil based ones break down the latex of a condom. Just make sure you don't put it on wrong and you'll be fine. Just make sure it's what you want to do!