14k gold lady Hamilton watch

This watch belonged to my great grandmother. It's 14k gold with 4 small diamonds on face plate. The band is stainless steel (Speidel). I know my grandmother was born in the 1935 & her family was considered wealthy. But I don't know how old it is. I was told by a jeweler from a pawn shop that I should get insured. I went to him to buy a battery for the watch. But he informed me it didn't need a battery and showed me how to wind it & set it. It works very well. Every time I wear it I wind and set it, and it lasts about 18-20 hours. 

Good