First off, I say finish it, cause "then he woke up" it's the lamest cop out in the history of writing.
Second...is she the beauty of the forsest, or the wanderer of the forest? If both, then what does her beauty have to do with anything (assuming her "wandering" is more dominate than her beauty, cause that's what I pick up on). Also, why is she wandering if she is a forest nymph and belongs there? Shouldn't she have a home?
Third. Insert a sentence along the lines of "It was a small girl" before you say "He asked the girl her name." It sounds better that you identify the person is female before they take action and assume gender at the same time.
Fourth. The tenses are off. Some times you use words like "continued" (past tense), then you turn and use words like "decides" (present tense). Pick one, I suggest past tense.
Fifth. I'm guessing the ending was just a cap on after you thought the story up, but you might want to think it through a bit further. Her trusting him, and him trusting her, came a little too easily. Why would she want him to guard the forest? He's an average human? How does she know he wouldn't hurt the forest himself? Does she ask every random human that wanders into the forest to protect it? Or did she call out to him?
Cute story Tommy. Finish it!!