How can I prove that I am responsible enough to get a budgie?

How can I prove to my mum that I am responsible enough to get a budgie. Last year my cat died, yah and this morning my chicken died as well (the chicken was not that sad but Casey was) and anyway last Sunday night I asked mum if I could get a budgie because I have always wanted 1 but she doesnt think I’m responsible enough and she has to “talk” to dad about it. She also says that I never looked after Kurmit, a crab I used to have but I disagree I did look after him very well and she blames me for his death saying he died because I didnt give him food or water, when I always gave him food and water and he died because mum was too lazy to take me out and buy some other bigger shells for him, so he died when he was molting (I couldnt go out by myself because I was in grade 3), mum admits that I do look after Ziggy- the cat like feeding her, but I take no responsibly for the chickens (I dont have to take resposbilty anyone thou because Thelma died) when I did take repsonsiblity like cleaning out the house and feeding them while mum is on holidays and when she is too lazy to get out of bed, but she never gives me a chance to do that anymore and then she blames it all on me and I’m like what the hell I have done this time??

So, I really want a budgie and I know all the responsiblites it comes with like cleaning their cage as they poo all the time, feeding them. I do have a currently vancant large space for a cage to go in my room aswell and then there is always Ziggy who would love to the bird (that mum is always worried about) :D not if the cat cant get into my room which she cant as the door is always closed. So yeahhh..