I'm electronic engineer from Lithuania. Last Friday I passed OCA 1Z0-808 with 71%. Not very glad with the result, but happy as hell
So, I'm 29 years old and hope you won't say that it is too late to learn programming
It took me 5 months of learning and before that I was absolute zero in any programming language so I started from scratch. I think I won't say anything new about preparation, I started with the book "Head first java", then of course OCA Oracle Certified Associate Java SE 8 Programmer I Study Guide Exam 1Z0-808 by Jeanne Boyarsky and Scott Selikof (special thanks, very good book), I have read it a lot of times
and finally Ethuware tests (it's definitely worth to buy).
I think next step would be learning a bit about android programming would be cool to build an app and of course OCP preparation. So, thank you all (I was reading success stories and preparation methods at coderanch) never give up, do not loose your patience while learning and good luck!