I moved out when I was young, almost too young depending on who you ask.
There are down sides, but the freedom is worth every penny earned, and subsaquently spent on bills. Your mom will get over it, she's probably spent meny years dreading this but in the end it's all a part of being a mother.
My relationship with my mother got far better after I moved out. when I was living with her she even called the cops on me once and had all of my stuff moved out onto the front lawn when I was 16. Now it's like none of those years even existed.
Congrats on the courage to move out. This starts the real test of who you are. You might make a few mistakes, we all do but hang in there.
And don't forget to tell your mother you love her.