1) There's no way to tell at this age whether it is male or female. It's way too small.

2) I don't think there is really a way to tell of age unless you specifically know when it was hatched or morphed at what day (Not sure where you begin to count a frog's age...lol)

3) Not sure what the "little white bug" could be, but I'd think about cleaning out its entire enclosure or changing the substrate to get rid of it just to make sure the bug isn't harmful.