Depending on how tall you actually are, the bike can vary in size. If you have a BMX bike be sure to have tall handle bars. Usually BMX bikes come in a 20 inch or 24 inch. If you think that your bike is too small, then go for a 24 inch BMX bike. I have a friend who is 6 feet tall, that can ride a 20 inch perfectly. But he has tall handlebars, so that is what i think you should do. Also, your friends may be able to do better tricks because they have been practicing, biking longer, or are just better. So don't think that you are bad just because your friends can do better tricks.