I feel like there is an assumption being made here that your dream to attend UPenn will translate into you walking up to this person and saying "Hi, I'm an MS2 and want to do neurosurgery at UPenn. Help me." Obviously don't do that for a host of reasons - you may not even know if nsg is for you, you may know nothing about the program and whether you are a good fit, the fact that you were a patient once is insignificant with regards to matching, etc.
With regards to being intimidated, you miss 100% of the shots you don't take. Never back down from an opportunity to network and seek advice. When you do approach her, just be candid and say you are a second year thinking about neurosurgery and want to know if she has any advice for you or can help you find ways to learn more about the field. If you are given any opportunities, show up prepared. If she lets you shadow, watch videos on how to scrub in, block out an entire day to shadow, and arrive early. If she invites you into her office for a meeting, be prepared with questions.
I first shadowed a neurosurgeon as an MS1. Showed up the first day and got yelled at before I could even put my hand out for a handshake and say my name. Life goes on.