I'm on spring 25 in my first year and I still can't use the first windmill Oo
That's pretty weird since I've read you should be able to use it at spring 23 in your first year.
Don't worry about it. During that time you have little events happen or the weather might push off the windmill event. Its happened to me mutliple times. Just wait and it will happen on the first sunny day that no one else is visiting you on in the morning.