I never understand this nub stuff.. I can't see anything
I'm going to apply this ridiculous "skull theory" which says if the skull is "round" it's a girl, and if not round it's a boy. Haha.. sounds so silly. But your baby looks like they've got a nice round skull so I'm going to say girl!
But in all honesty, I think it's still too early
My doc said they can't tell for sure until 18-20 weeks?
For my SIL, she was told she was having a girl until her 7th month, they were like "oops, it's a boy!" haha.
Good luck!