Mum trouble

Me and my fiancé live with my parents which we both pay rent to live there and still buy or own bits such a drink and by drink I don't mean alcohol we have to buy our own fizz and what not. I don't have problem paying rent as I was brought up that you respect your parents and you don't get anything for free. Once I tuned 16 and left school I had to get a job as well as go to college so I could pay rent or otherwise I'd have to get out. Me and my fiancé are getting married in October, it's just a small wedding with the people who mean the most and then we will be getting our own place as we know we couldn't afford to get married once we had our own place together so this order was perfect for us. We want to set up a joint bank account together but as the fiancé is busy working we haven't had the time so his money and my money both go into my bank account as we both trust each other 110% otherwise we wouldn't be marrying each other. My mum thinks it's acceptable to slag us off saying she thinks it's a stupid idea us putting our money together and trying to say my fiancé takes it all which isn't the case, the money that goes in is our money and we spend on things together we even discuss what we're going to be spending if one of us is out without the other so we both know what is in and out of the bank. I don't understand what is wrong with the way we are doing things and it angers me that my mum is being like this, it's not as if I've given a boyfriend if 2 months my bank details he is due to be my husband. My mum doesn't seem to have the trouble having a joint bank account with my dad and hiding his bank card and lying to him about what is in the bank, she also has no roblem with asking to borrow money off me when she's skint cos she's somet the rent money we've have her on whiskey😡😡😡