Masculine in a girl?

They CAN be signs of high testosterone. Except sitting with your legs wide open like a guy. That's just mildly bad etiquette.

But they can also be just how you are. Humans come in a wide range of shapes and sizes. Plenty of perfectly normal, perfectly healthy women have more hair than they'd like, or are muscular, or have deep voices.

hairy girls turn me on

Part of it is genetics, part of it is just your hormones, and part of it is your personality/upbringing.
The genetics and hormones are playing a part in the voice, the body hair, and the adam's apple. The hormones can play a part into you having naturally toned arms, but it could also just be what you do. My sister has super muscular arms because of her job.
Sitting with your legs spread out is just you, most likely from your upbringing or what you were exposed to at a younger age. This can be corrected, if you want to correct it. I sit like this in public spaces so I actually have leg room.

You must be very very young, or live isolated away from populations. Because all you have to do is look around and realize that not all women are the same. There are very feminine women, there are some that are masculine, most or somewhere in the middle.