why do grown up step children think its ok to disrespect just because they are of age now? My SD is 21 now and lived with us for 2yrs after her mom passed away in 2004. We never had any problems with one another until recently, I would say the last 2-3 years. After she dropped out of college and moved in with her girlfriend she has become quite the opposite of what she was raised to be. Today I am needing to vent about her RUDE and very hurtful comment to me.