Will it be risky to ask university to change my course?

I applied to uni of nottingham for psychology through ucas, however i didn’t realise i applied for a MSci (Bsc with intergrated Msc) rather than a Bsc, i immediately called and emailed asking to change and pretty quickly they changed my course at the same time as giving me an offer! I am so happy. However, I’ve found myself drawn to neuroscience since, (i don’t have required subjects to do pure neuroscience) however i would love to change my course from pure psych to psych + cognitive neuroscience to give me best shot at doing a Msc post grad, as i know often you require a biological science to do postgrad. But because I’ve already asked for my course to be changed once, and on top of that i now have recieved my offer, i don’t want UoN to not change my course and also remove my offer due to me being indecisiveness. Is this a problem?