How easy is it to sell on BrickLink as a non-dealer?
In general, it is considered best to first build up a reputation (i.e. feedback) by selling smaller items, before offering up rare and expensive items. When a new seller (low or zero feedback) offers up an expensive set, the following might happen:


Buyers will be afraid to purchase from you as offering expensive sets for sale by low feedback buyers is associated with scams.
You expose yourself to fraudulent buyers who are preying on new seller and try to pull a fast one (e.g. claiming something never arrived, or claiming something arrived damaged, or even returning something opened and replaced).


This is not to say that those things will always happen, but low feedback raises warning flags.

Of course, with proper research and careful shipping you can avoid all of this, and especially if you are competitively priced you might sell sooner rather than later. 

Being perceived as a scammer, or being scammed yourself, is something that is unfortunately a regular phenomenon on any marketplace, be it Amazon, EBay, BrickLink or Craigslist.

So net, just be careful and do proper research on how to best cover yourself against potential scams. Selling LEGO can be a very exhilarating experience!