I think it depends on your talents and passion. If you are truly excited about something and enjoy doing it, then it can't be too difficult for you.
Actually it depends on the exact branch of the engineering discipline.
Electrical engineering is pretty easy for some areas and hugely mathematical for others. Same goes for pretty much all the rest.
Once you get to post-doctoral research there's no such thing as easy.
Electrical engineering is definitely the most difficult out of those. All engineering requires a lot of math. If chemistry is easy for you, then chemical engineering is for you.
MEDICAL ENGINEERING IS THE MOST DIFFICULT ONE.
My sisters friend, who is in her 3rd year of environmental engineering, said that electrical engineering is way more difficult than civil, environmental, and chemical engineering.
