Honestly you are not forced to conform, and no sane Mythic guild expect of you to better follow suit in an army type of fashion without any deviations or you sit out. Not as long as your decisions doesn't impact your guild or raiding team negatively.
Guilds fighting for or aiming at world top 20 most likely expect that you'd be ready to go as soon as first raid opens, but are you in one of those? If not, please remember that you actually do have options and that you don't need to be forced to level in a way you don't enjoy. There are good semi hardcore guilds doing really well out there that don't play dictator over their members.