16 is way too young. 17 is kiiiind of pushing it, but I think that goes with the whole "Oh you're over 18, so you're considered an adult shouldn't you be with someone who's also 18 or over?!?" thing most people have. I know some people (mainly parents) have a problem with people in a relationship with someone 3 years in age difference, but I don't because my parents were that and they were alright. 18, no problem!
But I don't really date. Not with how most people do it. When I think of dating, I think of meeting someone new and going out one night to do something and getting to know each other. Every relationship I had so far developed from friendships, so I already knew them, they already knew me, and we were familiar with each other's families.