Most Helpful Girl
15/16 is a good age to start dating "unseriously" and college age (18-22) is a great time to start testing out more serious relationships. Obviously, people grow a lot during college, so many of those relationships don't last, but they do provide an excellent learning experience. I say 15/16 as a good starter age, because lower than that, puberty varies too much and setting a standard becomes impossible.
Most Helpful Guy
When you are ready to date you will know. But don't date too young as you lose most of your fun and life experiences. Children date so young nowadays and they are riddled with problems and issues from their partner. Set a goal with a career and once it's stable, then go find Mr Right.