You should be a Capricorn!

Capricorn Zodiac sign

People's lives controlled by Capricorn are known to be a persevering and dominant lot. Like a Capricorn, you are practical, willful and determined to reach your goals. For you, decision-making is a process -- which is why you're unlikely to act on impulse.

Don't be afraid to loosen up though. Things don't always have to go your way. There are a lot of other perspectives that you may be missing!