Luísa Sonza could hardly grasp that she’d be performing at Coachella until... well, she was performing at Coachella. “Representing Brazil, being there this year... it’s such a big moment,” she tells Bustle over Zoom of her festival debut in April. “I couldn’t imagine it would be so soon.”Hailing from a small Brazilian town, Sonza started performing in a wedding band at just 7 years old — a gig she’d keep through most of her teenage years, and on…