When someone says they are Muslims let them know you are so pleased they are seeking after God and that you are too. Then ask if they have read the Ko·ran/kəˈrän/ . If they say no ask if they are following the faith of their parents? After they answer share with them that you have heard that in the Ko·ran/kəˈrän/ it is written that Jesus was the only Prophet who was born from a virgin birth and how it is written in the Bible that Jesus’s mother was a virgin. Then ask if you can share about what He said about heaven. 
Then share the Gospel if they let you.