So my boyfriends ex just followed him on instagram. they have been broken up since high school which is 20 years ago should I b worried?

she has two kids and has been with her baby father for 10 years. me and my boyfriend have been together for 15 years. she still follows his family on social media and they like and comment on each other stuff. she also tells my boyfriend happy birthday every year on his family shout out post. is this girl just being a pest?
So my boyfriends ex just followed him on instagram. they have been broken up since high school which is 20 years ago should I b worried?
Post Opinion