In my opinion they will find out regardless,of If you tell them or not. Via accident or you forget your ear is showing yada yada. Just tell them and let them in easy
Dam, you sound like you are bleeding to death over there lol. But I would have recommended at getting punched at 4mm at most, because now it's gonna take your ear a lot longer than 6 months to heal I'd say almost a year and you'd be in the clear to stretch. But enjoy that piercing man!!