well I'm 19 now, and started puberty a little later than most guys (I didn't even have armpit hair until grade 9.) My chest hair is starting to come in though. I've had a treasure trail for years, and about a year and a half ago I started noticing really tiny, thin hairs right in the centre of my chest between my nipples. Since then, the hairs have gotten longer but not much thicker, and have been creeping out horizontally towards my already-fairly-hairy nipples. My treasure trail has also started to surround my bellybutton and move up the center of my abdomen to connect with my chest hair.
I really am nervous about how it's going to finish out though! I don't want to be a bear. My dad has barely any body hair, so I hope that means that I won't have too much. I'd like a nice chest coating and even stomach hair is good too, but I don't want it to be thick and bushy, and really hope it doesn't spread to my back. My arms and legs aren't very hairy either though so I think that's a good sign.