Take this quiz!
Since the picture isn't so large:
Your patronus would take the form of a unicorn. Unicorns are fierce, solitary but magnificent and selfless. They are quite brave and always mysteriously beautiful. Unicorns are symbols of unconquerable pride and purity. They are impossible to tame and are very rare. The horn is said to protect against poisons, Unicorns signify chivalry and dignity.
It might be great to someday be as definite about myself as these quizzes seem to be. haha. :)