I think it is a lovely name! I like it much more than Ava, in my opinion. Maybe I'm just biased though because this is my name hehe. But honestly, Avia has quite a classy and mystical kind of charm to it, and flows very nicely on the lips. And I also like that it's very rare, so I've never met another Avia before, n' I'm always the only Avia in my school. I love having a unique name! I LOVE MY NAME AVIA! :D.
It doesn't sound masculine at all. I like it a lot better than Ava! Ava is just too short and ends too soon so that's why I would say this one is much better!