Your looking at about 18 months wait mate if you want engineering in the army Application, english, maths and barb test, get medical sorted, pre ADSC, first interview, second interview takes 6-9 months, then a few months wait for ADSC (Army Development and Selection Centre) depending on how well you scored in your interviews and Pre ADSC tests then about 12 months wait for training. They are full right now and very picky with who they recruit, they can afford to only take the best now.

My advice would be to be keen, very clear on what you want from the start and get your running shoes on now.