fine to use?

We like the name Isa (for a boy) but I have a 5 year old cousin named Isabella. She lives back in my home country. We visit every year for 3 weeks and during that time we only see her maybe a handful of times, if that. Last year we only saw her once but we are connected through social media. My other concern is that Isa might sound like a nickname for Isabella so that could be confusing. When I mentioned the name to my mother, so assumed it was a girls name because it is extremely feminine sounding in Spanish. Thoughts?