Is it still probable cause to get a rabies vaccine covered by insurance if u were bitten 3 years ago by cat and incubation could be 6.5yrs. scared!

Doubt it: The rare reports of extra long (to 25 yrs) incubation listed with the NIH are based on case histories. And an assumption that the victim did not have another exposure. Most consider the risk negligible if you are more than a year out from exposure. You should share your anxiety with your doc and see if the fear represents another issue.