your married, wrong type of visa for a spouse, and you can't get a spouse one because shes not 21.
but if your coming together to the uk, you might be lucky and get a visit visa for her, but there is a chance she will be refused, because the classic refusal excuse, they dont believe she will go back b4 her visit visa expires.
thou you might be in luck soon, there should be a judgement on a court case regarding the gov raising the age to 21, so who knows, it could go back to being 18yrs old.
