What do you think of this name for a boy?

I really like the name Luca, but some people have said "that's a girl's name!!" It's a very popular name for guys in my home country of Croatia, I guess Aussie people just don't get it. We will be raising my bub as an Aussie, and I don't want him to get ridiculed at school if it sounds like a girl's name. I was thinking of lengthening it to Lucas, but I have always just loved Luca. What do you think of the name? I don't know the sex of bub yet, keeping it a surprise, so may not even be a boy yet :-P