'Priorities' when coming out

Hey folks. Okay so a little background on me might help: I'm 16, male, gay, and currently out to my Mom, Dad, sister, and a few close friends at school.Recently I was having a conversation with my dad about me wanting to come out fully and be open about it, and my dad suggested that certain people (e.g. grandparents) might feel kind of offended if they weren't to know first - sort of like 'how come I didn't know before everyone else', or 'how come I found out by being told by a friend who knew before they told me'.Do I owe certain family members any 'obligation' of sorts to tell them first? What are your experiences in situations similar to this? Any/all help is appreciated!