I would strongly advise against it. My grandmother's sister in law (in other words, her brother's wife) was the product of first cousins. She had many many health issues throughout her life and her 2 daughters have a lot of problems as well. Several of the doctors over the years have specifically told them their problems were likely a direct result of the too close family relations. I've grown up seeing them with problem after problem and I don't suggest to anyone to put themselves into that position. In my opinion due to witnessing the result of this is that it should be avoided at all costs.
It sounds to me, delux, like you are expected by family to marry this girl and you are resisting.
I've always been interested in genetics and genetic populations, and I will say, in general you're pretty safe marrying a cross-cousin. (A cousin where the genetic linkage crosses gender lines as in your case, the genetically linked ancestors are not the same gender - it's your mom and her brother). Sometimes you can get something that's recessive and harmful in a population and it takes over because of interbreeding. Like albinism. In general, if your family is healthy and you are healthy and so is she - and her mother and your father are not related for many generations back, you're really at no more risk of having a child with a chromosomal abnormality than anyone else.
I'm sensing the bigger question here is - you'd really rather not marry this girl and would rather make your own choice. Is that it?
I guess it would depend culterally what goes on where you are from. In the US, marrying cousins is taboo. So, it wouldn't be a good thing for the stigma of it.
I also agree that it is a big world---- lots of peole to marry that aren't already at our family reunions.
good luck
Where do you live? I know in the US, in a lot of places, it's actually against the law to marry a first cousin.
The other issue is with having children. If you plan to have a family, you are at a significant increased risk of having a baby with birth defects and other problems.
My personal opinion would be to tell you to seek out someone you are NOT blood related to. There are plenty of women in the world to find a mate.