I would highly suggest some type of intervention. We are lucky to live where we do and have the resources available to us. But most county’s have some type of resource. I can recommend a book: PreSchool Stuttering, What parents can do. It teaches the proper approach, reactions and even some tips to help. But, your kid will know they are stuttering (trust me) and other kids will too and they will not react the way you want them to, which is why you need positive reinforcement and a speech pathologist. One of the most heartbreaking things about it is the lack of confidence and unwillingness to engage with new friends. And that can lead to much bigger issues. So please, find a Speech Pathologist and do weekly one hour sessions. Totally worth it.