No longer under my mom's culinary insurance and i have braces, help!?!?

okay so ive had braces for a year and two months and my moms insurance [culinary] was paying for them, not every dime of course, we paid half also. Now that I'm turning 19 they said it can no longer cover me unless im a student enrolled in college, and if not enrolled theyll have to remove my braces:[ im not in college because of financial problems, my mom is a single mom with 5 kids so i work to help out. What can I do so the insurance can still cover my braces? They also mentioned COBRA, how does that work?