Are Buddhists superstitious? Believe what the fortune teller said?

Of course not. People who believe in Buddhism are people with faith. They believe in karma and use it to urge themselves not to do bad things. It's totally different from superstition. People who believe in superstition and fortune telling are often people who lack knowledge. They don't know much about science, so they don't believe in science, so they are forced to blindly believe what fortune tellers say.