there is a reason why everyone on this board doesn't believe claims that you were competently riding doubles on your very first day (pretty sure you had this same argument with someone else about a year or two ago).
I don't know what a double looks like where you're from but at most places a double is ungroomed, about 12 feet wide, and/or littered with moguls and/or an in-bounds gladed area. IOW, they are trails which require advanced intermediate to expert competency, which no beginner has. Ever.
FYI "falling 20% of the time" pretty much constitutes total failure. I'm picturing a trail that spans maybe 1000 vertical feet with 15 or 20 falls between top and bottom. That ain't "riding a double black" that's "surviving" a double black.