Lets start off with the premise that your mom loves you and wants the best for you. I say that with confidence, because if she did not, she would not care where you went to college, or if you went at all.
Now with that said, let me say that you are not alone out there in the world. My wife was adamant that our son not attend a JUCO because as she put it, it was like going to a 13th year of HS. When I came to this forum about a year ago, many here recommended JUCO as the right fit for my son. Frankly I got sick of hearing it because I knew my wife would never allow it, even if it was the right thing for my son baseball wise. Coaches of D1's along with JC coaches offered to speak with her to let her know their perspectives, but she would not budge.
So while I doubt she would "disown you", she might very well harbor some ill feelings toward your choice if you go that route.
My recommendation is to have her read through this forum to where she can see that you will need exposure to get on different coaches radars. The days of being discovered playing HS ball are coming to an end unless you are already a stud played, or live in an area of high visibility(which you do not).
If she reads that other moms or dads oppose JUCO's it might help her understand that she is not alone in that belief. Once she feels some empathy, she might let her guard down long enough to consider other possibilities such as showcases, tournaments like PG's event in Jupiter, or maybe a camp at schools she would approve of.
There are many paths to playing in college if you have the talent and drive, but you cannot sit at home hoping the phone will ring. Furthermore, she will come to understand that just walking on for a tryout is not a sound strategy.