Recieving Organic traffic on a site nearly created?

So admittedly I'm only just starting to dip my toes into online blogging, I've been learning the basics of SEO while building up my blog. I'd say I'm around 25% of the content complete before I can start looking to add articles every day to try and increase my rankings in the searches.

What's odd is today I woke up and checked my google analytics for the crack of it, just making sure its all correctly set up and what surprised me was to find that someone had clicked through from google on to my website.

What I can't get my head around is how this would have happened like I said the site is only 25% complete with barely any SEO is done, I know for obvious reasons I won't be ranking anywhere on my site so how on earth did someone manage to click through from google?

Also, one other question while posting this thread is that I read on google that %75 of their traffic is click-throughs from the first page with pages 2 and 3 seeing a dramatic drop. Am I right in thinking if your on say page 16 of Google with your keyword search that you shouldn't expect any organic traffic as no one is going to click through to the 16th page of results?

I should say i do have around 27k words currently on the site.

It’s pure luck I feel also if you’re not on googles first page then you’re missing out on lots of traffic

There's nothing surprising here. For a new site, you have almost 30k words. Probably the click has come from some ultra specific long-tail phrase. Also, it's happening often at Google to give a little boost to new websites in order to see how they're performing and if the users actually like them (view different pages, stay more on the site, etc.), so called Fresh index.