Please help! really low level people when I have been playing for 2 years!

Hello, I have been playing League of legends for about 2 years now, and I am sure that i have been getting better, and playing with better people, because I have noticed the change in skill of the people I have been playing with. Anyways, today I played 1 match of LOL and was playing with a level 6, level 11, level 9 and level 14. I have no clue what I have done to play with these people. I just got really frustrated with them and left the game. Any help? Please? thanks in advance!