I was born on a cusp. Which sign is mine?
Being born "on the cusp" means your birthday falls within a day or two of the Sun moving from one sign to the next. Astrology still gives you one true Sun sign, decided by the exact moment of your birth.
If the Sun changed signs on your birthday, your birth time settles it. Even so, it is common to feel traits of the neighboring sign too, especially if other planets in your chart sit there.