Year of impossible

I want to set a goal to stop drinking and lose 50 lbs in 2021. It seems impossible because I’ve tried for a long time to do this. I guess my question is, I don’t understand how I can simultaneously believe it’s impossible and still go after it fiercely. And if I have 25 epic fails per quarter, what does this look like? Drinking when I said I wouldn’t, eating a cupcake? I don’t understand how the failure part works in terms of wanting to fail and getting good at it. I feel like I already know how to do that part in regards to overeating and over drinking.