I think I started lifting around 17, when I was 6'2" and 170ish. I was on the poetry magazine and didn't do any sports in school (just studied martial arts outside of school). At one point, I got called 'lanky' something like three times within two weeks and finally decided to train.
Routines were straight out of bodybuilding magazines and changed every few weeks. Took a ton of supplements instead of food (working at a GNC didn't help). Turned down advice from bigger/smarter lifters because I was reading plenty of magazines and I "knew what I was doing".
Basically plinked around with half-assed plans until I was well-out of high school, eventually got certified as a trainer and finally started getting things in line.
Ha, yeah that's a double-edged "feel proud/feel like a dick" moment for sure. I had it happen once when I had a bar loaded and sitting on the rack, dude walks up between sets and asks to work in, he does a bunch of short-ROM shrugs then steps aside, I do snatch-grip high pulls while his eyes bug out.
Dan John probably has some of the most relevant insight and experience in this arena. Some of his standards were just posted in another thread:
"I've found that when a high school boy does over 200 pounds in the bench press, clean, and front squat, good things seem to happen. Here's my "Big Blue Club," the basic standard for being a Varsity athlete:
Power Clean: 205 pounds
Deadlift: 315 pounds
Back Squat: 255 pounds
Front Squat: 205 pounds
Standing Press: 115 pounds
One-Arm Bench: 70 pounds (5 right/5 left)
Power Clean & Jerk: 165 pounds
Bench Press: 205 pounds
This should be easy enough for the boy to do all in one training session. I also have standards for push-ups (45 in a minute), pull-ups (5 real ones), and horizontal rows (24 in a minute. I keep the feet on a bench so it doesn't become a leg exercise)."