I do feel for you but to be frank yr age would be the biggest stumbling block for the cadetships. Late 30's say 38 for Eg means you are well behind the 8 ball there sadly:-( I started late commercially (30 yrs old) & back then I was considered way too old but I persevered and changed trains ending up fly with the Airlines anyway, just went about it differently:-)
As much as you must be disillusioned plenty before you have ridden the same sad train but that doesn't mean your train journey need come to an abrupt end, change trains & ride it to another proposed destination:-)
Good luck, there's only one thing you need to succeed (other than LOTS of cash) is determination, that's free!:-)