I would like to be able to say to you that you will never face opposition such as this again Marie, but the Truth is as a Christian you will face all sorts of negative suggestions and even insults of various reasons while ministering to others/serving God as a follower of Jesus.
I too have been told I look too young to minister at 27, and for simply speaking the Word of God in Truth with confidence, gentleness, respect I have been ignored, spit on, threatened, called all sorts of names, screamed at, told I could never be a minister without a certain college degree, etc.
satan attacks our thoughts, but God's in control. When satan tries to put thoughts of self-defeat that are untruthful in our heads, we are forgetting to put on the Armor of God.
Jesus said, "Keep in mind that the world hated me first."
Remember what they did to Him. Remember who we are serving. Remember that we are "citizens of Heaven." Remember that suffering leads to character. Suffering for Christ is Joy!
I wrote a book about suffering in Joy for Chirst:
http://www.jiloa.org/JILOA/Articles/Suffering.html
This book is my attempt at ministry, but I have been told that since I am not an established writer, since I do not have doctor in front of my name, since I am not wealthy, etc that it is not a book of ministry. Same thing with my online ministry: It's a waste of time, no one looks at it, you're too dogmatic, you're a holy roller...
Jesus said in the Bible for Christians to not be surprised at the trials we suffer, but to never let it stop us from serving Him.
Suffering in this world is only temporary.
Moreover, the Bible tells of the importance of meeting with other Believers for encouragement/refreshment, and to get in the Word daily to expose insulting lies with the Truth.
I agree with the other comments in this thread. Communicate how you feel to your Pastor or another Believer. Show this person what you have learned about service for your age in the Bible- the indisputable Truth.