We all make mistakes in parenting at times—we will yell at our kids, lecture or nag them, rescue them from their mistakes, punish them harshly, etc. This does not surprise God. He knows and He is willing to forgive it all. You can surrender your guilt and your shame to Him. He will take your selfishness and neglect, too, if you turn to Him and confess.
That's a great relief! God is in charge, and He is willing to work alongside you to raise your kids. When you do something wrong, He will help you model humility as you confess your sin to them and ask for their forgiveness. Sometimes God even uses our mistakes as opportunities to connect with our children in a more personal way.
Rely on the Perfect Parent and He will purify all your mistakes.