I told my Best friend I like her and she told me she likes me too but what do I do ?

Dude, I'm telling you from personal experiences. I liked my best friend and she liked me and I had sex with my best friend and now we don't even talk anymore. It's awkward and it's disappointing. Dating your best friend can be a good or bad thing. Good because your best friend knows you like no other and you guys are comfortable enough to establish a relationship. Bad because relationships can get ugly and it's not worth messing up a good friendship. Ultimately it is up to you if you want to further that. If I were you, then I wouldn't go no further until you guys are on the same page about certain things.