Normal matchmaking system

I know this must have been written so many times, but I really wonder, although I am an unranked player who only plays normal and with only 47 wins, why I get matched with enemy players with over 500 wins and from silver, gold and platinum divisions. Is it because normal game matchmaking is not very accurate or the system is not working properly? I was planning to start ranked games soon, at least make my normal wins over 80, but seeing my win rate and my enemies' skill, I am a little bit intimidated. I started the game two years ago, I have two 30s in different servers. I was just a casual player who only played ARAM. Now I'm tying to change that but this is a bit... unencouraging. I know I'm improving, I can see the difference myself, but at the end of the day my game history is full of red. Did you have similar experience when you were new in the game? Do you have any suggestions? Should I just keep on gaining experince although I often get matched with silvers, platins and golds?