theres this birthmark on my eye i had since i was born..
i believe it didnt change in shape or size at all,
but im just wondering if it has to get surgically removed
or if its threatening or not..
Since you are old enough to come here and type and it isn't interfering with your vision and hasn't changed in shape, it's most likely unnecessary to remove it, although you may want to do it anyway for cosmetic reasons. The rest the info in the link provided should tell you what you need to know.
I was once told by a doctor that the dark area in my eye is most likely from trauma to my eye as a baby. Your eyeballs always stay the same size and yet the face grows, so the mark may not have been visible as a baby. I have also been told by another doctor it was a birthmark. It's not a dot; it fills the entire left side of the white of my eye and varies in color from brown, tan and red. Also, if I'm tired it is much darker. I wonder. Eye doctors don't seem to know much about it.
It sounds like you have ocular melanocytosis. If you'd like more information I'll be glad to chat with you. I've been seeing a specialist for it since I was born, although the birthmark has remained benign and I've experienced no complications. You can message me if you'd like