Should I just go with Kaiser considering how close it is?

I’m 26 in Northern California and buying insurance for myself for the first time. I haven’t gone to the doctor in years and I’m worried about some potential health issues, and I don’t have anyone to help me with this. I don’t understand most of what I’m doing but my big question is this:

My most important decision is between going for a PPO (Blue California, Anthem Bluecross) or Kaiser HMO. The big factor is that I have a massive Kaiser medical center about 500 meters away from me, about 2 or 3 blocks. The next closest hospital is about 3.5km away.

With this in mind, my thinking is that if I have an emergency then an ambulance would likely take me to the Kaiser center and I’ll want to be covered there. Does that make sense? I mostly stay around this area so it makes sense to me in theory, but I might be missing some nuance.

Also, can I just get on a really expensive plan, have them check me out to see if anything is wrong with me, and lower my plan in the future if it turns out I’m fine?