That’s a tough decision, I guess you should start with really thinking about engineering vs medicine
They’re extremely different but both are challenging and good careers. Ask yourself: do you really want to potentially spend 10 years training to be a doctor? If that puts you off medicine, maybe you should drop biology
Whats making you think about both options? If there’s one you really enjoy and one that you’re considering ‘because it sounds impressive/gets a lot of money/ my family want me to do it’, then that’s probably not for you