It is interesting to compare Ovid’s account of creation, following Greek-Roman traditions, to the Judeo-Christian account as recorded in Genesis. There are some striking similarities between the two, but also important differences. The two accounts concur in their depiction of an orderly Universe brought out of original chaos by a creator, and various developments in stages thereafter, culminating in the formation of man from the clay. However, unlike in Genesis, which clearly relates the story of the first man and woman, Adam and Eve, the first human beings created are not named, or even individualized, in Ovid’s account.
The two accounts are similar in depicting how to begin with humankind was good and pure but fell into sin, but the set-up in either case is quite different. In Genesis, the human fall from grace is enacted in the first man and woman, Adam and Eve, whereas in Ovid’s retelling, this fall takes place over various ages; there is a gradual descent from the perfect age of gold, reigned over by Saturn, through silver and bronze, to the final age of iron which is full of wickedness.
Perhaps the most fundamentally important difference between the two accounts is that in Genesis, all of Creation is clearly attributed to God the Supreme Being, whereas the identity of the creator in Ovid’s account is considerably more haphazard. Ovid simply talks vaguely of a god, or Nature, being responsible for creation. This is in keeping with the whole world-view of the ancient Greeks and Romans who believed in the existence of a variety of gods, rather than a single supreme being, as in the Judeo-Christian tradition.
To answer your second question, there is no particular reason given as to why Daphne should want to remain a virgin. However, there is a clue in her invocation of Diana/Artemis, the virgin goddess of the hunt, who always resolutely shunned all attention from would-be lovers, and indeed, often took violent action against them. It seems that Diana is something of a role model for Daphne and that is why she behaves the way she does.