I read somewhere that the 45% of people had the same rising sign as their sun sign. 45% had other sign for their ascendant, and the other 10% of the people adopted another sign for their ascendant. These people's personalities were shaped by their environment.
It could be that you are one of those people in the 10% category, or that you Identify more with your sun sign. These is more common in males than in females, as some women identify themselves with their moon sign.
My brother is an Aries who has an Aquarian moon, and his ascendant in cancer. When I told him that his personality sign was a soft, sentive, emotional, and tender cancer. He said the reading was way off, and told me not to beliefe these astrology nonesense. His hard headed, Ariean-self didn't want me to explain to him what all that meant, and his aquarian moon makes him too detached and logical to care.
However, you have to keep in mine that the ascendant only shows how you appear to others. It does not say who you are. The ascendant gives you the physical characteristics of that sign, and it shows how you deal with life challenges, and how you behave when you are with strangers. The esoteric meaning of the ascendant describes how you are going act in order to achieve the mission of your sun, because at the end of your life's journey, the sun (sign) is what you will become.
If you don't know the time of your birth, just put 6:00 A.M. as your birth time. This time is excellent for finding your ascendant when you don't know your exact birth time.