Me, I look for the First Lady to be a woman of God who can set an example for the women of their church body and others outside (being another church or unsaved) of how to live holy and righteous before God. I would only expect her to be obedient to God's Word (Logos and Rhema). All those other expectations(i.e. run the children's ministry, lead Praise and Worship Team, etc.) that people try to put on the first lady and even the pastor are MAN-INSPIRED.
So I encourage you, if that is what God is calling you to, go ahead and walk in it. Remember the word requires the preacher to give their attention to prayer and ministering the Word (Ac 6:4), and to properly shepard the flock according to 1 Peter and John 10. As long as you are doing these things and whatever else God gives you to do, then you are in right standing with the most important person, Our Lord and Saviour Jesus Christ.