Finally! I wondered how people actually know that the genetic code is the same in every cell. How would you prove that? What if everyone is a chimera to some extent? We are just getting started understanding epigenetics.
For all intents and purposes, your DNA is the same in every cell. We know this because we can pool DNA from multiple cells and sequence them. We see orders of magnitude more variation from sequencing error than true intra-isolate nucleotide variation.
Yes epigenetics exists, and it influences our development and habits, but it's not going to change the content of your DNA.