Is my older cousin acting insecure?

You said she comes from a not so good child hood, as in economically. She probably is just proud of herself for making it this far, and she wants you to be proud of her to, maybe say "I love you, but why do you need my compliments? I've very proud of you for everything you've done, but it's starting to come off as bragging" You could also do any other kind way of putting it, its your choice. Hope this helped, have a nice day <3