which branch is more difficult electrical engg. or mechanical engg.?
You get to build stuff doing electrical engineering as well, for sure. It's just different, and will depend heavily on the school you go to (some are almost entirely theoretical, while some, like my school, focus on projects so you get a lot of hands-on experience).
So, I would recommend electrical, but it is up to you, of course. Also, depending on where you go, you may have a taste of both before needing to declare a major as some lower classes are required as a base for both fields (at my school, again...) That can help you decide - if you like statics a lot more than circuit analysis, then maybe mechanical is the way to go.