My 3 month's daughter is sucking her thumb all the time. What should I do?

Hi She is just 3 months old and I found not think you can do much right now as she is so small that she would not even gather that by taking out her hand from her mouth, you are implying not to do it. It is comforting for her to suck on her thumb when she iz not taking your feed or not latched. I guess let her be and when she starts understanding then do things to distract her from thumb suckling.