Those people pursuing the "milestones" for purposes of self-image are insecure and need counseling or therapy. The milestones are not some recipes for happiness. Figure out what you want, "you want" not what you think society expects.

There is not a one size fits all life that will make everyone happy. Yes, if you buck the standard some people will express dissatisfaction. I would not choose what is expected just so someone else is not unhappy. You don't owe your parents grandchildren; you don't need to have a partner or be monogamous or be hetro or be a homeowner.