Hellp me please :'( please :'(?

I'm sorry to hear that. First of all don't panic. It's a hard thing to take a child's word over an adults, so you have to be very careful. This is going to be easier to say than to do, but if you can do it, your mom may believe you. Answer calmly and listen to what is being said by your grandma. Lies have a way of contradicting themselves. Hold your ground no matter what. The question you need to ask your mom in private is, where did I try to hit my aunt at and where. Have her ask your grandma and aunt seperately so that your aunt and mom don't have time to get their stories together. This should get your moms attention. Both of their stories shouldn't line up.