I have a couple questions, I am currently aged 14 and cruise around 69-72 mph. and top out at 73 mph.I am a 8th grader going into High School, my goal is to throw 82-84 Senior year, I want to know if it's realistic also I am left handed, so I would like to know my chances for college and if so what kind.
I think your goal is very "realistic" and doable. You may even be underestimating your potential. And while it's particularly hard to know what your physical development might be (a lot depending on your genetics, genetic background regarding size and athleticism and whether you mature early or later), if you happen to reach average velocities for High School, you're likely to be in the mid 80's rather than the low 80's. So, thought you haven't described you're physical make up or what physical attributes might run in your family line, I would suggest that having a higher goal would help you achieve more than you think you can at this point. That you here asking such questions and already have good outside coaching (from the sound of it), suggests to me that you have the interest and drive to achieve more. Being goal oriented and with a desire for college ball, YES. . . you have good chances for college ball. Just what level of college ball will depend on how well you develop your skills.
If you raise the bar a little higher than what you really think you can do now, you very well may find that you can do much more than you thought you could. :-)