Should I go for my childhood friend? If I do, how should I go about it?

I know you said you know the risks but I lost my best friend in the world this way and it still hurts to talk to him. Now, that being said, ask him if he thinks you guys should try going out, chances are he feels the same and is having the same reservations you are. You both sound like sensible people, tell him how you feel and see what he thinks. If he is your best friend, he will tell you honestly his opinion.