I'm attracted to my 2nd cousin
I hope you're joking. How long have you been attracted to them?
It goes back to when I was 5 years old.
Becoming attracted to someone when you are young isn't the same kind of attraction you feel as an adult. Regardless, it can be difficult to control who you are attracted too, but you do have control about who you choose to date.
What I'm trying to suggest is why can't I date her?
You cannot date her because you are related. It is wrong and probably illegal. It would be healthier to move on from your cousin and find someone appropriate to date, maybe with the help of counseling for unresolved feelings.