All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
Allaah Willing, there is no blame on you if this baby girl, who is in her suckling age, goes to her father or other men naked because she has no ‘Awrah at this age.
Therefore, scholars permitted that men can bathe a baby girl of suckling age and the like of whom a soul has no desire. Khaleel Al-Maaliki said: “And a man is like a baby girl of suckling age (i.e. it is permissible for him to bathe her).”
In conclusion, there is no harm in this, Allaah Willing, although it is better and more right that you should observe concealing her ‘Awrah. Rather, all of her body should be concealed so that she may get accustomed to this and thus be raised upon concealing her ‘Awrah and having modesty.
Allaah Knows best.