i to have learned a massive amount from this site.
here's briefly how i got into strength & conditioning, as a coach.
i was a computer science major who was always into basketball/athletics. one day i decided to switch majors. eventually i got my bachelor's in exercise science. self study has gotten me to where i am today though. note-taking/research/experimenting is absolutely essential.
prior to getting my degree i did a volunteer internship at a performance facility. there i realized i wanted to eventually train college/pro/elite athletes. there i worked with middle school, high school, college, mlb/nfl, and an 2006 nfl combine class. i always got hyped when training, or assisting in training, of the elite athletes. i wanted to try all of my own progressions and ideas on these athletes, but of course that wasn't going to happen.
so i left there, did my internship, landed my current job as an s&c coach at "memorial sportscenter" in pembroke pines florida. proved myself by putting some great results on people who were preparing for tryouts and "combine-like" testing events. so now i work with elementary school level, middle school, high school, college, minor/major league, arena football, and various other non pro/pro athletes.
every monday/tuesday/thursday/friday, i absolutely CANNOT wait to go to work. it's too much fun. my first training session consists of minor/major league baseball guys, football players, etc. it's a big group. in a group, everyone works harder. the guys who don't mind getting filmed, love the damn camera. i take my mac, and video their pr's or things they want taped, and put it on my youtube. it's always interesting, because every athlete is different. different goals/imbalances/deficits/strengths etc. so it always keeps you on your toes - which eliminates the boredom factor.
when testing day comes, i get really hyped up. i get nervous, hyped, excited, etc. i feel like my rep (even though i don't really have one yet) is on the line. so in some weird way, i feel like i'm the one being tested. so every inch they add to vert/broad jump, or tenth/hundredth that drops off their sprinting, when they reach their body comp goals, when they get their goal numbers at a combine/testing event, it makes your day, week, year... etc
i don't know what kind of trainer/coach you want to be. all i know is that being a strength & conditioning coach doesn't feel like a job. it's too much fun.