Others have commented on the rest, but I would just keep in mind that PTSD would be more in the wheelhouse of psychiatry, not neurology. You're not expected to know 100% what field you want to go into yet (though there's no harm in having an interest - I went into the field I was most interested in prior to med school), so I wouldn't pigeon-hole yourself too much in interviews. Especially if your understanding of what neurologists do is a little off, as that may work against you.