freeze up is usually due to fear of being judged and the desire to be liked, “I don’t want to say something she won’t like, should I do this, should I say that” meanwhile you are frozen. So honestly you just have to be you and do you and if she doesn’t fuck with it then you didn’t want to be with her anyway. There is no special time to do it And just be straight up, “I like you, do you want to go on a date”