It definitely takes a while to get used to climbing hills or even mountains. The biggest factor in climbing is you. I'm referring to your weight and your training.

When I got started, climbing totally sucked! I lost weight and road every hill I could find until I was ready to conquer the mountains. It took about 6 month and about 2000 miles, but now I don't think twice about it.

I ride with a compact 10 speed 11-28 cassette. The typical climb gradient I ride is between 4% and 10% and the length is between 2.5 and 6 miles for each mountain I climb. Occasionally I ride multiple mountains in a day.