Answer:
In general, the risk of bleeding from a 4mm aneurysm is less than a larger (7mm) aneurysm; however the risk may vary depending on the location, morphology, and other characteristics of the aneurysm.
Therefore, I would recommend that you follow up with a vascular neurologist (or vascular neurosurgeon and/or neurointerventionalist) to evaluate the MRI images, your medical history, and other factors to help you decide the best plan of care.