From Longman Dictionary of Contemporary Englishlate developer/bloomerlate developer/bloomerMI a) a child who develops socially, emotionally, or physically at a later age than other children b) someone who does not become successful until they are older → late
Examples from the Corpus
late developer/bloomer• He was bright, but a late developer.• He was what you'd call a late developer.• The latest developer claims to have carried out extensive research into the feasibility of providing medical treatment in Darlington.• I suppose you could say I was a something of a late developer in two out of three.• Although a late developer, it began to take on the size and conformation of an excellent Clydesdale stallion. 