How appropriate is it to go by Michael for a girl?

I’m a trans FtM teenager and have been for quite some time, but I currently have to stay closeted for another year or two because of my family situation.

I’ve wanted the name Michael for a very long time and have gone by it online for years. My birth name is Sophia, which I never particularly liked even before realizing I was trans, and I’m honestly getting pretty tired of being called it. At this point, I subconsciously think of myself as Michael.

Only about four people know I’m trans (three close friends and my sister), and I’m confident they’d accept me going by Michael. My school is also pretty accepting; staff will change a student’s name upon request without requiring parental permission, as far as I know.

The problem is my family. I’m not ready to come out to them, so if I started going by Michael at school, I’d have to explain it as simply wanting a different name. My sister already goes by Arin instead of her birth name because she disliked it, so I could potentially use that as an explanation.

But this is the part I’m unsure about: Is it weird/inappropriate to go by Michael while still presenting as a girl and staying closeted?

I really love the name, and I’m getting increasingly uncomfortable with my birth name, but I’m worried that using Michael while still presenting femininely might be strange or make things more complicated.

I’d really appreciate some outside opinions.