Teenager endured a frustrating wait for his registration to be approved but took no time to show his potential on the big stage against PSG At first glance there was the usual stuff: the wide smile, the guttural release, the punch of the air, teammates quickly on the scene to offer congratulations. But then the real celebration followed for the 17-year-old Brian Madjo. After scoring his first Aston Villa goal 45 minutes into an unforgettable debut , the teenager clasped his hands behind his bac…