I feel like a failure. I'm getting really bad grades in school even though I can do better but I don't care about school at all. Also, a while back I sold one of my moms rings to get money and the other day my mom said she lost her engagement ring. I can't live with myself knowing I sold my moms engagement ring what should I do

I would try to get the ring back, tell her if you can't. It will be harder to recover the longer time passes.
Right now you probabbly still need money and have no ring?
A Job would help. Good Luck.

I may only be 14 but I can give advice, or at least my friends think so xxx
If you think its too hard to tell your mum, get the money (a job would help) and go to her with all the money you can get and tell her everything and why you did it, yes she probably will be mad, but she will get over it, she loves you more than a silly ring, which is replaceable, unlike you. As for your attitude about school, just try doing better, maybe before you tell your mum, its never a good thing not to care about school, think when you can't be arsed doing work, think about your mum, and what you did, think the more I try the more your mother will be happy. Maybe tell a friend what's been happening and maybe the'll help too!
Hoped this helps!
Amy xx