How long would it take a cerebral aneurysm to rupture?

Dont know: I dont think anybody without an 'eye' (like a crystal ball) for the future can date this.

Unknown: Average age of rupture of brain aneurysms is 52. It likely takes a few years but this is so variable. Aneurysms are rarely seen in kids or people less than 35 years of age. Additional factors such as uncontrolled hypertension, smoking, connective tissue disease may accelerate the process to an aneurysn rupturing. Using Cocaine is also known to accelerate rupture.