Are you going to be a dealer, a tire-installer, or eventually a lead mechanic?
I hope you have what it takes. You really need a maaaaaaaad passion for it.
If you want to be a mechanic, you'll have to find you're way into a competitive bunch and build relationships.
You will be stressed, break down, throw tools and cry. So unless you love it more than any sane "normal person" you might end up divorcing the moto life.
Give up on women too. They'd never go for a guy that works on motorcycles all day. Ask me how I know.
Before you make any commitments, buy a bike for $300. Anything, really, as long as it is mechanically complete. You need a motor that ain't locked up, includes the carb and rolling chassis, as well as a mostly un-ratted wiring harness. Having a key can help, but learning how to jimmy an ignition can help too. I say complete because it's the stupid shyeet that is impossible to find. I own a 1977 Lincoln Mark V and all it was missing was the flex-hose that connects the carb snorkel to the intake funnel just behind the grill, for a fresh-air intake. Yeah, check for yourself, they're gone. Non-existent. I had to burn the old felt off of the steel inner structure and wrap it with aluminum tape. Same goes for a lot of bikes, like finding a primary chain for a CB77 Superhawk or an idle mixture screw for an '88 KDX200.
Get it running. Then get it running well. Then paint it and add new tires and chain. Then learn how to rebuild brakes, both discs and drum. Plan to spend all of your disposable income, then plan to spend money you don't even have. Wear some sort of hat, whatever suits you. It ensures that when you want to throw the nearest object at the bike, it will at least be soft and convenient. I wear a crushable felt hat so I can really rap on shit and come out unscathed.
Each process you tackle on your $300 scrap heap will be a large part of any learning curve, so take it one step at a time and ENJOY each one thoroughly. Ask lots of questions. Ask so many questions that people just stop talking to you, so you're left to figure it out. In the end, you'll either have one hot little mud slinger to be proud of or you'll have a great post for the Craigslist "gem" of the week thread. It all depends on if you really love bikes as much as you need to to hang in there.
I've run my own shop for the past 4-years and living off of instant pancake mix and Ramen so that I can afford an impact wrench here and a valve-compressor there has long lost its whimsy. Soon, though, I should be considering water and a stove.
Somehow I keep doing this crap every morning, but the sort of conversation I have with the local ferals seems to make things evergreen and the sun has stopped screaming about mankind's innately vulgar egalitarianism.
Feel free to PM me when you start your restoration thread.