The young defender featured in a 3-0 Carabao Cup triumph over MK Dons in August and is looking to build on that performance.
"There is no price tag on me but when you say it like that, it's kind of mad," said Simpson.
"To think where we were and where we are now is exciting to see – there are no limitations for this club.
"I still have a long way to go. I would like to be one of the best players the club has produced but I have a lot to prove.
"To push myself into the starting XI is the aim for every player and that is what I have to do.
"The lads have been playing well so it doesn't make it easy but I will be there trying to push and, hopefully, it makes healthy competition."