It may or may not be a sign but DON'T give up on the criminal justice thing either. You may find that this will come in real handy. And I agree that as long as you feel led to work with youth and that you really like it, keep going until you hear other wise from God. He will let you know if he wants you somewhere else. God bless and good luck It is a wonderful thing you are doing 

It could be a sign from God or it could not. The first thing I would suggest doing is pray about it. [Ps 37:4,5] "Delight thyself also in the Lord: and he shall give thee the desires of thine heart.Commit thy way unto the Lord; trust also in him; and he shall bring it to pass." God doesn't always give direct signs to show you what you should do. It could just be something that person whanted to ask you. The lord will give you a peace about what he wants you to do. If you choose to go into the ministry or not, God will still use you. The most important thing is that you are living your life for him. If you delight your self in the Lord, he will give you the desires of your heart. If you ask God for wisdom and pray to him about it, just be patient and you will eventually know what he wants you to do.