Read the following article and answer the question.

We also saw horses ... and almost hit a deer . We tried to get Holly to watch the Demitri Martin CD , but she fell asleep . Instead , we all packed up and gave in to slumber . In the morning , we got up early , and drove back out to Assateague . There were n't too many people on the beach .

Why might Holly have fallen asleep before anyone else ?
She was not used to so much fresh air and it made her feel sleepy .