First, I applaud what everyone else has already said to you in this thread. You’ve been given some great advice–for a person in your circumstances the very best advice I’ve seen, IMO, is for you to find a good pitching coach who will work with you on a regular basis. There is really no substitute for experienced guidance and you should note carefully that several people have included this advice in their remarks to you.
To make the point more clear, I suggest that you take a look at the following clip of Dinesh Patel:
Dinesh and his compatriot, Rinku Singh, are from small villages in rural India and neither of them had ever touched a baseball, or even seen a baseball game, before competing in a throwing contest that eventually allowed them to come to the US to study baseball pitching. They may differ in some ways from you because they both had some amateur experience throwing the javelin and both were athletic enough to have decent raw velocity for throwing. However, neither of these guys had ever held a baseball in their hands until they were 19 - 20 years old, and that’s where you have a tremendous edge.
It may surprise you to learn that these two 19/20 yos learned enough about pitching and baseball in about 8 months to be signed to minor league contracts by the Pirates late last year. Was it a set-up…? Well, yes and no. Both guys were gifted enough to throw the ball hard, without any further notion of what pitchers actually need to do in games. There was definitely PR value to be gained from any successful outcome of this experiment. However, when these guys got their try-outs in front of MLB scouts last Fall, nobody could go out and perform for them–after only 8 months of focused training they both showed that they could consistently throw strikes with several types of pitches and field their position. They both touched 90-91 mph with fastballs. No one could do that for them (not even Public Relations people who can sometimes appear to make silk purses from a pig’s ear). Both are currently playing rookie ball for the Pirates organization, never having touched a baseball before they were 19 or 20 years old. Is that clear enough?
You share at least one terrific advantage with these two guys: If you have never played baseball before, then you have not spent years throwing a baseball with counter-productive mechanics. So, you will not need to spend lots of time overcoming deeply-ingrained poor habits.
Assuming that you are athletically inclined, focused on your goals, and willing to do the physical work necessary to accomplish your goals–a good pitching coach can help you get there.
If you think you can’t afford lessons from a good coach…find a way. If you spend your time doing fruitless experiments without personal guidance from an experienced coach, you’ll find yourself going backwards when an experienced coach could really shorten some trails for you and help you keep moving forward.