Is it wrong for me to feel a sense of pride for being successful, whether it is in school, work, church, etc.? How am I supposed to serve with humility in Sunday School? Is it pride to feel good when someone praises me?
There is nothing wrong with being successful. God asks us to do the best in all our endeavors; as long as we acknowledge and give credit to him for our success. For, without Him we can do nothing. Pride comes when we attribute our success to ourselves ignoring the fact that it is a gift from God.
Being a Sunday school servant and a leader is a great way to serve the Lord as long as we direct the eyes of those we serve to the Lord; and give all glory to Him not to our knowledge. Compliments should never divert our attention from God as being the source of our success and the cause of those compliments. St. Paul says "But by the grace of God I am what I am" (1 Cor 15:10).