I have a basilar artery fenestration without aneurysm. i am 36. i am worried an aneurysm will form or a stroke. ive read that aneurysms for 7% of the time. that seems high when speaking about aneurysms. should i be worried? what do i do?

You certainly do not have a fenestration in your basilar artery, By definition fenestration is "a perforation in a structure". You may wish to restate your question or better yet, consult a neurologist.

This is an uncommon anomaly of the basilar artery that you were born with. Since it's so uncommon, I recommend consulting a neurosurgeon with expertise in vascular disorders of the brain for evaluation, advice & follow-up. I would suggest calling the department of neurosugery at a university hospital near you to locate such a specialist.