What is your full name? Do you know why your parents chose that name for you? Were you named after an ancestor? Someone famous? Do you have a nickname?
Why you say is it important to get the full name of the ancestor? Well for one thing it was very common to get the middle name of many of our ancestors from surnames on the maiden side of the family. In my genealogy I had a middle name that was used repeatedly. It turned out that two generations down the line it ended up being a surname. This is very common.
Knowing why someone used a particular first name may offer clues to past generations. Naming traditions were very common in many ethnic backgrounds. The first born son was named after the fathers father, the first born daughter was named after the fathers mother, second son was named after the mother's father, second daughter after the mother's mother and so on down the line. Please understand that our families were not real creative in coming up with regional names. A relative uncommon name like Magdalena can be popular when naming traditions are involved.
A common name to someone famous does not indicate that your ancestor is related to that person somehow. It is common today to have research done to prove relationships to people that are famous. Proof is not always there.
Finally pay attention to nicknames. My own grandmother was named Babe for the first five years of her life, because my great grandparents could not decide on a family name. Surprisingly these names appear many times in public records. Checking several sources will help in finding the true name.
So when doing your interviews be sure to ask questions that will offer solutions to problems that may be created as you do your research.