kids who won’t put their face in water

so one of my kids, who’s about 4, will not put their face in the water by themself. whenever i tell them to when their swimming, they tell me to do it for them. they are completely fine when i put their face in for them, but will not do it by themself. it’s been weeks of me doing it for them, and i just don’t know how to get them to do it by themself.