Everyone presents an idealized version of themselves on the Internet. Though we may be able to fool our rank-and-file Facebook friends into thinking we are smarter, cooler, or tougher than we actually are, there is no fooling mom and dad. If you are fronting a little bit too hard for your folks' liking, don't be surprised if they deflate that ballooning ego by telling your online friends what you're like in real life.
Don't hate them for it: honesty is the best policy. Your parents taught you that, or at least they tried.