If it contain some specific contents which can be associated to the ownership/country then changes to the same would be a problem. This is the reason, you must elaborate in more detail about the contents of this website.
Moreover, you are a newbie and here in this forum it's recommended to use escrow to deal with. Instead of asking for 50% in advance, I think you should allow the buyer to use escrow..
Yap, OP needs to provide more information about his offer.
I would like to see the website link and any proof of traffic. Also, I need to know if there used any of paid marketing tool or paid traffic.
thanks