What do you think of this excerpt from my book?

Assuming that this is of the young adult genre... outstanding! You got it sister. The only thing I might suggest is that this could be smoothed out a little more, with the connecting points between the sentences a little more defined. Also, I think adding more clever, less general descriptions that coincide with the seascape setting could make it better, along with some character though and emotion to put the reader firmly in his shoes. That is merely my opinion, however. Really, it is good to go.