WHAT’S IN A NAME?
It’s a common practice these days when meeting people for the first time to call them by their given (or “first”) name, regardless if the person met is older. It has a certain democratic attractiveness and works comfortably enough in informal, social settings.
Business settings are something else. Older persons usually are more senior and may view the younger person who calls them by a first name as impertinent or presumptuous. So, it’s safer and wiser to call this person Mister or Ms and let the older person urge you to use a first name. This is especially true if the older person has a hard-earned title like Doctor, Professor, General, or Senator.
When meeting someone from another country, and especially when in that person’s country, always use a respectful title like Mister or Doctor, regardless of age. Non-Americans tend to be more formal than we are, esteem titles and rank, and may resent what we consider simple friendliness. This continues to apply even after you’ve gotten to know someone well. The present author has been amused (but silent) when Asian, Latin, and Arab friends call him “Ambassador Chase”, a sort of halfway point between formality and informality.
Of course, none of this applies in Hollywood or Silicon Valley, where informality is a given and where many rules of proper business and social behavior are suspended. Still, if you’re up for a big job at the studio, be sure to call the fellow in the sweater and beard sitting on the other side of the desk “Mister Spielberg”.