Go for your dreams! I'm glad you have one. I'm afraid I can't do much for you, but I'll share the post and hope other people have a better idea than I do. One thing is for sure though, you'll need to practice a ton (I've heard going over a speech in front of a mirror is really important)! I wish you the best.
''Demosthenes lived in Athens from 384 B.C. to 322 B.C. As a young man, he suffered from a speech impediment—which may have been a stutter, an inability to pronounce the “r” sound, or both. He designed a series of exercises for himself to improve his speech. According to legend, he practiced speaking with stones in his mouth, which forced him to work very hard to get the sounds out. When his diction became clearer, he got rid of the stones and found he was able to enunciate much more effectively than before. He also practiced reciting speeches while running and speaking over the roar of ocean waves to improve his projection. These strategies must have worked, because Demosthenes achieved fame as the greatest orator in ancient Greece.''
You can do it!