I hate to be too harsh, but at the end, this is your life. Explain the best you can and if she won't understand, you need to make the decision best for you, not for your mom. You will later regret your decision and resent her perhaps. Buck up, send emails, make a video, ask your HS coach to help, if JUCO is the only place you get to play ball..YOU make the decision. If your mom won't support you, that's a problem with her not you. I'm sure you love your mom very much, but she cannot live your life. If you are passionate and love the game, you should go for it.
"The education isn't horrible." (Posted by Low Finish)
Gee, so kind. Is Algebra different at Harvard than City CC? No. Do thousands of years of History change in the CC textbook as compared to Princeton's? This JUCO/4 yr stuff is all ludicrous. Yes, the IVY and elite schools have very intelligent students and professors. But the academics, with regard to general studies, are the same everywhere. The same subjects are taught all over. Besides if you have the smarts to be initially accepted at such schools, you will be fine no matter where you go. It's all a bunch of hooey. While being able to secure admission to such great institutions is an incredible accomplishment, it's not the end all be all.
Sounds like you have it very tough! I feel for you and hope it works out for you.