No one should "want to be a pro bodybuilder" it doesn't work like that. If you go into the gym and blow up like a nickel balloon just from looking a weight, and if you have crazy perfect structure, and are a complete and total nerd (required), then you could think about competing someday in half a decade or so. By the time you step on stage, you should know if MAYBE you have a chance at the national level.
AND, all of this has to be just HOBBY.
There is not "I want to be an astronaut" crap, those are lies society tells kids. You don't "become something" you simply are what you are. Jobs don't define us. College is a scam. What you "do" in life is be yourself, nothing more.
Also, remember the biggest factor isn't just your response to gear, but your tolerance to gear, there is no way to predict this.
FINALLY, remember this, most pros are just bodybuilder hobbyists, you need a real life outside bodybuilding. Only a tinny, tinny handful of pros are actually making a living at it.