By Kieran King Kobbie Mainoo’s rapid rise continued earlier this week after he earned his first England call-up. The 18-year-old has impressed during his breakthrough season at Manchester United. In fact, the teenager has started in 15 of their last 16 matches despite only making his first Premier League start in November. Mainoo was initially called up to the England Under 21s squad for the March international break. However, after putting in an excellent performance in United’s 4-3 win over Liverpool, Gareth Southgate decided to call Mainoo up to the senior camp ahead of friendlies against B…