Andrews' deal runs until June 2022, plus a one-year option.
A former pupil at Langley School, the Solihull-born Andrews has been at Blues since 2009.
The powerfully built 18-year-old stands 6ft 3in tall and he causes problems for opposition defences due to his presence alone.
Not only can Andrews be a focal point of the attack because of his size, but he possesses a good touch and is nimble over the ground.
He featured regularly for the Under-23s prior to the season ending prematurely, as well as for the Under-18s in the FA Youth Cup.