As others have said, your gorgeous little bird is most likely a Sunday Conure, a Sun/Jenday cross. Suns can have that much green when they are babies, but usually lose it by the time they are several months old.
On the issue of feeding Sunflower seeds- Obesity is a problem for lots of captive parrots, but Sunflower seeds can be very useful. I, personally, think they can be a very good addition to the diets of Conures and Macaws in particular. These birds, in my experience, do better with higher fat. My family raised and handfed probably at least 1,000 Macaws and Conures over the years and always found this to be true. Of course, the main staples of the diet should be a good quality pellet, fresh vegetables, some fruits, and sprouted seeds if possible.
One of the most expensive and touted pellets on the market is Harrison's. Our bird vet pushes it like it is crack for parrots. Guess what the NUMBER 1 ingredient is- Sunflower seeds.
Also, the pelvic bone method of sexing is very accurate if the person knows what they are doing and the bird is in good health and breeding condition. With Conures, I can easily get 95% accuracy. The key though is that the birds must be in good breeding condition. The pelvic bones in males will be close together, usually no more than about 5mm apart. The female's pelvic bones will be a little more than a thumbs width apart (to allow egg laying). Again though, the key is that the female needs to be in egg laying condition for this to be accurate. DNA sexing is so cheap and easy though that you might as well do that. The pelvic bone method was useful to us when we were buying hundreds of birds out of quarantine (the days when you could get most Conures for about $10). We did not have DNA sexing at that time. Birds were sexed via surgical sexing which was a huge expenditure of time and money.
