Definitely looks like your server for the most part for the first time load. It looks like you have most things set up well, compression, etc.. Your caching could be improved but that will not help first time page load which is your main issue.
You could probably tweak your settings a bit to get that time down though I am more familiar with Vb4. I bet some added server resources would help immensely..
https://www.webpagetest.org/result/160926_TW_VDR/
https://www.webpagetest.org/result/1...irst_byte_time