Svetlana's parents migrated to the US before she was born, they were both political refugees from Soviet Russia, her grandfather having been found to be a traitor by the powers that be. Her parents barely made it out, her grandparent's didn't.
Svetlana was born only days after they arrived in the US, and grew up never knowing the oppression of her parent's homeland. While Svetlana was of only average intelligence, she had a focus and mind set that was scary in its intensity. She didn't excel at her studies, she stared them down and wrestled them into submission, forcing herself to learn everything the teachers put before her, and then pushing herself even harder.
By sheer stint of hard work, she graduated high school at the tender age of 15. She immediately started college, and again by a force of will that left her professors breathless, she pushed through and gained her bachelor's in 2.5 years. Another year and a half saw her gaining her M.D. in general medicine. She then signed on with the Navy as a Naval Surgeon.
Despite her low coordination (normally an issue for a Surgeon), her focus and methodical approach made her one of the higher rated Surgeon's during her stint.
Eventually, given her native fluency in both Russian and English, she was approached by The Agency to be an Agent.