I meet Alexandra Sheppard on a sweltering September evening. She’s travelled down from North London by bus to meet me at the Southbank Centre. She’s dressed in denim dungarees, her hair is pulled into a top knot and she has that baby-faced youthfulness that probably gets her carded all the time. We’ve met once before, at a Black Girls Book Club event where I got her to agree to a proper sit down so I could get all the dish on her highly anticipated debut novel, Oh My Gods.