Do you/like it shaved

Male and female humans are born with roughly the same number of hair follicles distributed in the same pattern over our skin.

Hormonal changes at puberty mean that as well as the development of pubic hair in both sexes and men developing beards, the colour and thickness of hair in other areas of the body also changes for both sexes. What exactly happens depends on the roll of the genetic dice at conception, but all women naturally have arm hair. For that matter, they also naturally have chest and back and facial hair. It's just that the hair there usually isn't very obvious since it tends to be fine and light-coloured.

I am a girl and have a lot of hair, underarm too

The only woman I've seen with lots of arm hair was a supermarket cashier. She had a unibrow, mustache and had arms hairier than mine... (A normal guy).

But every other woman I know, or have been with just has fine arm hair that isn't really noticeable, unless you look closely. It don't bother me, but whoever is dating the sasquatch at the supermarket should invest in a laser hair removal gift card XD