If you genuinely have an interest in engineering, go for it. It will be far more helpfull than than working in MacDonalds.
I served an engineering apprentiship before starting my ATPL course and it helped immensely (I started it at 18 and was the youngest one of the group). I'm now a time served mechanical fitter turner with 8 years experience and have an (F)ATPL. Having a trade behind me has let me keep my options open and I am now in a position to decide that the airline route isn't what I want but the engineering route is.
(So if anyone knows of any engineering jobs out there please let me know, I'm itching to get my hands dirty again after doing this pilot lark for 3 years.)