How Do I KNow That I Sing Good?

I am turning 13 in 5 days so i cant audtion for american idol but i want to know if i can sing good. My friends told me that i sing really good and one time when i sung this girl bless the brocken road by carrie underwood and rascal flatts and she started crying and told me it was perfect. And i tried out for a talent show and i was one of the people in the call backs but i didnt get the part that i wanted i got candyman kids ( it was willy wonka and the chocolate factory) so how can i know that i sing godd. i tried recording myself but i still dont know if i sing good because its like me listing to it like i wont know if people accually like how i sing. so please help me