Morning Class??....no..

Today, I woke up early in the morning. My roommates are preparing to attend their classes. " Why did you still lie on your bed?! Don't you have to attend for your morning class? " One of my roommates claimed. She made an assumption that I woke up early because I have a morning class, but actually is not. "When will you go out?" She asked. "Later." I answered. My answer is over-generality because the statement is not sufficiently specific. When is 'later'?? 'Later' can represent 10 minutes, 1 hour, 2 hours or even longer period.