trancebrah
How difficult is it to fly a helicopter?
Compared to what? 
Learning to fly takes study, effort, and "want to."
And money, as noted.
If you are studying science in college, and doing well, you have the mental acuity to handle the ground school/scholastic angle of preparing yourself to fly. You may also need to look into a medical exam. When you contact the flying instruction school, as suggested above, they should be able to recommend why, when, and possibly a few "who" in the local area.
I learned to fly a fixed wing aircraft before I learned how to fly a helicopter. Hovering for the first time was humbling. It's learnable, but I'd say it's an acquired skill. A good flight instructor will see you through.
Flying is fun, for sure, but it's also a deadly serious undertaking. If you take your friends up flying once you earn a pilot's license, you have their lives in your hands. Please remember that the first time you do take a friend up. Things can go pear shaped up there ... so if you take no other advice from "old hands" than this, remember this priority list
Aviate
Navigate
Communicate
Your instructor will of course wish to drill that into you as you learn to fly. May as well have the mantra embedded in your long term memory ahead of time.
Best of luck. Study hard. Take it seriously.
I hope you are able to fund your desire to fly. It's a wonderful thing to do.