That's where this comes in handy!
It's called a Natal Chart.
"In natal astrology, a natal chart is a horoscope/astrological chart drawn for the exact time of an individual's birth at a particular place on Earth for the purposes of gaining information about the individual." — wikipedia
The neat thing about Natal Charts are that they aren't nearly as cut & dry as your sun sign is. For example, my sun sign is Cancer & I am a Cancer native through & through. But my Ascendant (shows our natural defenses and how we cope with day-to-day issues. It's basically the mask that everyone wears.) is a Libra. Which makes a lot of sense because I am ALWAYS trying to make sure that everybody is happy. I'm big on neutrality & Cancers are actually known for not being very neutral & rather over-protective. lol.
It explains all of it in your natal chart. It'll give you tons & tons of personality quirks that you can run off of. I didn't explain it TOO well, but if you give it a try, you'll definitely understand better!
Hopefully I helped somebody out!