Don't even bother until you're 16, at that age go out on dates but stay single, no BF/GF drama. At 18 do the BF/GF thing but understand this ahead of time , you WILL get your heart broken at some point in time, but you can reduce that risk by dating around first before committing to a relationship.
I say do it whenever but keep this in mind.... You will most likely not stay together and if you are to young it might mean almost nothing to the other person. Dating doesnt really get real until like 16 or older.
Honestly. Me being a Christian I don't dive for boys, and I don't go for any boy. I wait until God puts one in my way, and if it is meant to be then God will let it happen, but I think if you believe in God then the right person will come at the right time. TRUST!