S/he is a very pretty bird! I'm not very familiar with this species so I don't have much insight on the behaviors. Head bobbing is either a sign of aggression or attention seeking, you just have to look for signs. Half raised wings and a slightly open beak would be aggressive, while curiously...
With parrots, it can be really hard to tell the gender by just looking at them. You will most likely have to take him/her to a vet to get him/her vent sexed or however else they do it.