If I were you, I'd omit anyone who is living from your tree on ACOM if you want to have a public tree. You're probably not going to find a lot of records for living people anyhow. Aside from that, you probably have 1st hand knowledge of the living relatives in your tree. That's not to say you shouldn't have documentation for all the life events for the living relatives, though. I'd just keep that offline. My public tree starts with myself and follows my family back from there. I didn't put my siblings, children, or grandchildren in my public tree; just myself then worked backwards.
If other, younger generations of your family want to see where they fit in, they can easily figure out where their connection to your tree is and go back from there. If they're interested enough, they can start their own tree here with themselves and work their way back in time, documenting each person and generation.
I would just take care in what is made public because once information is public on the Internet, it's probably there for eternity whether you want it to be or not.