Identifying Avics, especially as larger slings and subadults, is a very tough deal. Hopefully the source you got yours from was a good one and in that case you can trust what they said it was. If it hits 5" and keeps growing, and growing, and growing....and growing, then is 7" yeah it's a braun I've got an adult if you ever wunna compare pics, but to me they are just an overgrown A. avicularia or metallica. Whatever it is Avics are awesome T's!
Now im sure it's a braunshauseni - it has that distinctive red hairs on it last pair of legs ,it would be cool if it could turn out to be a metallica ,love to have one of does .. but they are too expensive here in Bulgaria ..