How do i find out exactly what God wants me to do?

by S.An Gutsa
(England)

I'm an average teenage girl. My life has been pretty interesting even to myself. I'm far from being the perfect person on earth, in fact, i'm a great sinner. However, i am Christian and I strongly believe in God. I try to be good and sometimes i succeed, sometimes i fail. When i was small, I would pray to God and see it being done! they say children's prayers are more powerful, because they are not yet sinful (Mark 10:14)could relate. When i was 13, i learnt at a boarding school in Africa and my dorm mate was ill and losing her vision. I put my fingers quickly in front of her eyes to check if she was feigning or not, and surely enough she wasn't faking it. Something inside told me to just put my hand over her eyes and pray, which is what i did. After a short prayer, i asked her to open her eyes and her sight was back. Everyone started calling me pastor, i was flattered but thought nothing of it afterwards. Then at 16, i went to a church Easter conference where I gave a testimony about how i had almost died. everyone, or at least those who said so, was touched by my testimony and my short preaching. I kept on sharing testimonies at church and sharing good stories as examples (kinda like parables but not from the Bible).
Then yesterday, I'm 17 now, I casually went in front of the church and gave my testimony. Afterwards, a lady stood up to give her testimonies. however, that testimony was about me. Apparently, she had seen this sorta vision and she saw that i've got a calling from God and i could help people repent, because she had been touched and greatly moved by my testimony. i couldn't believe my ears, me of all people, being chosen by God to help bring forth His sheep. I'm still confused, this is new to me. The pastor told me to fast about it, but today i failed. I intend to fast about it and wait patiently for God to reveal to me the path He wants me to follow. I would love to strongly believe i was chosen, it's just that i'm not a very good person myself anf i'm scared that i might not fulfill this task. I'm scared that i might chicken out and not do God's work when it genuinely is Him calling me. Please help me, how would i know, i would i find out what He trully wants me to do. I'm only 17.