I want 2 work for an allowance!?

mom has always said she wants a beautiful yard with cedar fences and flower beds but we have none of that. We have a huge dirt spot in our yard! dad wants a shed 2. I have told mom i will fix the yard and told dad that me and my cousin could build him a shed because i need an allowance so i can have gas money! but they say "no,you wont do it you wouldnt last a day outside" but ive spent the last week cleaning off our neighbors fence row! how can i get them 2 let me do it?