As always, most of this is conjecture. That's why I call them "theories of relateeveety"......
Stephanie Douglas was born into wealth, with her father John being a rich businessman in Chicago. She attended Northwestern University, where she gained a reputation as quite the party gal (unlike the reputation she built later in life as being a woman of strong moral conservative values.)
Stephanie was dating a college classmate named Massimo Marone back in the 1950's and they slept together when they went off to Geneva, Switzerland, for a vacation. But soon after they broke up when Stephanie met and fell in love with Eric Forrester. Unbeknownst to any of them, Stephanie was pregnant with Massimo's child. However, since she had also been sleeping with Eric at that time, she naturally assumed Eric was the father of the baby whom they named Ridge.
After graduating from college and marrying Eric, Stephanie Douglas Forrester didn't want to trade on her father's name, wealth, and power; she was going to make it on her own. And so she forged her own career path in Los Angeles, one that could lead her one day to gain her own position of wealth and influence. Eventually she landed the position of secretary for famed gossip columnist Lilly Bentley. Susan Flannery was first seen - officially - as Stephanie in 1987 in the second episode of 'The Bold And The Beautiful'. But as the unnamed secretary for Lilly Bentley, she made one quick appearance in an episode of 'Burke's Law' ("Who Killed Harris Crown?") in 1963. By this point, Stephanie and Eric had been married for a few years and were adding to their brood with Thorne, Angela (now deceased), Kristen, and Felicia. With the strain on their finances because of their growing family, Stephanie wanted to make sure her dream of making it big could still be realized. So she went to John Douglas and asked her father for a major loan with which she and Eric founded their Forrester fashion firm. She quit her job as Lilly Bentley's secretary but may have used the contacts whom she met there to get the business off the ground.
But she never looked back - which is why it's never been mentioned on 'The Bold And The Beautiful' that Stephanie once worked as a secretary as seen in an episode of 'Burke's Law'.....
One last point:
Stephanie has never learned that her father had an affair with a married woman named Nelson. John Douglas fathered a daughter and even though there was a decade's difference in their ages, Stephanie Douglas Forrester and Edith Nelson looked exactly alike.*
The power of tele-genetics!
Like her half-sister Stephanie, Edith also started out in an office position. But thanks to the influence of her older brother, Admiral Harriman Nelson, she served as a stenographer in the West Wing of the White House. (This combines two characters Susan Flannery played on 'Voyage To The Bottom Of The Sea', from the episodes "Traitor" and "Hail To The Chief".)
Now, that was during the administration of President Henry Talbot McNeill. But this Toobworld timeline vanished becaue of a course correction to the TV Universe. This was due to a temporal reboot caused by Nick Cutter and his wife Helen when they traveled back through an anomaly to 'Primeval' times. Whether Edith Nelson still held the position of stenographer at the televersion of the Nixon White House in the adjusted timeline is unknown, but likely.
'The Bold And The Beautiful'
'Voyage To The Bottom Of The Sea'
* Although Susan Flannery's appearance on 'Burke's Law' and 'Voyage To The Bottom Of The Sea' were roughly a year apart, 'Voyage' took place about a decade into the future......