Technically, the first day of creation week would probably start at dawn, when God created light in verse three. However there is no reason to suspect that this was not immediately after the creation of heaven and earth as described in vs 1-2. In fact, Exodus 20:11 states "For in six days the LORD made heaven and earth, the sea, and all that in them is , and rested the seventh day: wherefore the LORD blessed the sabbath day, and hallowed it.". Therefore the creation of the heaven and earth (and the sea, the water you refer to) within the creation week. He may have created the earth in what would have been the morning, and then created light at lunchtime. Who knows? However he did it, he created it all on the first day, even though the earth was created while it was still dark.
It is sad that most churches do not do in-depth studies of creation. This is because it is a very hotly debated issue, and churches generally don't want do get involved. Or in some circumstances they don't care, which is very sad. Or speakers are free to say whatever they like without the minister making a stand on it.
The fact is that the bible clearly states how creation happened. Any 5-year-old can understand it. And there is an enormous weight of scientific evidence being accumulated showing that the YEC position is certainly not contrary to science. In fact, I find it affirmed continually the more I study science. If only churches would get involved as well as online forums. My parents have been basically kicked out of a church for believing in YEC (although that reason was very under-the-table and would not be spoken aloud). Incredibly sad.