No.
I could just leave it at that, but it wouldn’t be a very good post if I did. Search engines, in particular Google, update their algorithms constantly to improve the quality and diversity of results.
Imagine you are on a diet, getting to number 1 on Google is like reaching your target weight or dress size. SEO and Link Building are like a geeky, virtual version of going to a weight loss group down the Church Hall on a Thursday. You do well every week and lose weight at quite a fast pace towards the start, but then you plateau and don’t seem to shift anything for weeks.
Like your keyword rankings, you will find that your site will climb quite easily through the lower rankings over the first few months but may get stuck around one ranking for a while. This is because the competition is getting tougher. You might even drop a couple of rankings sometimes, just like you can sometimes put on a few pounds one week. This might be because you have snuck a few cheeky biscuits or it is more than likely just one of them things. Rankings like body weight fluctuate naturally, so don’t worry about it!
The best thing you can do for your keyword rankings, is not to think about them at all. Be as natural as you can with your site. Write relevant content, keep a blog which you update regularly, don’t stuff keywords and don’t build lots of bad links.