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, I feel that Avia has quite a classy and enchanting kind of charm to it. 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!
St. Avia (Ava) was the niece of King Pepin. In her childhood she was blind but was miraculously healed by St. Rainfredis. She became a nun at Denain in Hainault, now in Belgium, where she later became an abbess.