HELP!?!?!?! family issues!!!!?

I stole a few of my moms checks. And I wrote one out for 8,000 dollars. And I already cashed it and everything. I am just scared to find out what happens when she finds out. Anyway I can prevent her from finding out! I already spent 4K of it! Should I just kill her? Becasue thats what I am thinking of doing. PLEASE HELP!!!??? I am 21 By the way.