What should I do? Accept this gift or what...?

Okay so my boyfriend found me this locket in a box of coins his grandma gave him. And I never met his grandma. So I'm not sure if I should take it. And I have never formally met his mom and step dad yet. I'm going to probally next weekend. If I do accept it. Should I wear it when I first meet them? Idk what I should do.