Confused on how the MMR system works

As a new player to LoL, I have began to play ranked and I am currently placed as Bronze 2. I'd say I have been playing fairly well in my recent ranked games but I have noticed to have a very low MMR score compared to the rest of the people in my division (According to op.gg). I know this is only numbers, but it has an affect on the amount of lp gained/lost at an average of around 19 lp. I want my MMR to increase so I can climb easier and if someone could explain this system to me, it would be much appreciated. Thank you for your time. My MMR and match history if anyone is interested.