The Korean Language is based on Honorifics meaning depending on who you are talking to and the age of the person. When studying Korean it is best to learn the most respectful pattern of speech first. That way you will never offend anyone. The first question issued in a conversation where age is unknown is: How old are you and is not offensive to ask. Then you adjust your speech to the age of the person. I wasted 2 years of language study because I based my studies trying to tackle the grammar but Korean Language is best learned by life situations.

It is the same meaning. If you go deep into grammar, there might be a little difference. well I dont know that. However in our real life, we use that two expressions to express the same sense. "I am hungry."