There is absolutely nothing wrong in getting married to this girl. According to law, you are one hundred per cent the most eligible bachelor, to get married to this girl.
However, there are cases where marriages between relatives, even if they are distant relations, as in your case, are discouraged by some doctors, who point out the dangers -- the possibility of some defect in the case of children.
Am told that there is a huge amount of medical research and knowledge available in this regard. What you need to do is to visit a very well known gynecologist in your area and seek his/her opinion, after the basic tests are done. Such experts can guide you so well.
I know of some cases where these tests have been extremely useful, in knowing if there is any problem that needs to be addressed, from a very scientific point of view. In one case, where both the sides had medical doctors, it did become so easy and the wedding went through only the gynecologists on either side, gave a green signal.
Please do take the scientific route and do not, repeat do not, go to any astrologer. No astrologer, on earth, can ever predict the future. He or she, will try to match the horoscopes and then come up with some explanation. Since you are already in love, only the scientific route can help you to remove any doubt. However, in your case, such a possibility is very remote. I have observed problems only where the girl gets to marry her own maternal uncle or his sons.