FIRST TIME VISIT TO SEOUL :) (Seoul)

Hello all,
I am coming from Los Angeles to visit South Korea for the first time, I would love suggestions , on where to stay safe and good centered location, not overly expensive, tours to take, and places to see. From the point of native or from someone who has lived in the country for a long time. I am a Female traveling solo and would appreciate a freindly advice.
Best to all,
Stella