Nobody here can read minds.
If he's REALLY your "best" (male) friend ... You should be able to directly ask him.
You have to tell your mother or other trusted adult. Let them know what makes you feel this way. Be honest. No matter how old you are this is not an easy conversation. But you have to tell someone........ Don't keep this to yourself
It means that she totally likes you. Ask her out if you feel the same way but don't lead her on and tell her about your feelings if you don't feel the same way
You can be casual. E.g.: Hey that sweater you are wearing looks very good on you. You should wear it more often
