Start as a pen tester then get distracted by girls and booze.
You say that like its a bad thing. ;-)
Just sort of fell into it. Did an internship at university in $genericbigcorp and didn't bother looking for other/better jobs at graduation. (To be fair they paid a generous joining bonus - well £2000 "generous" to my broke 21 year old self).
That's the path of least resistance. Just passively accept calls and interviews via recruiters, and next thing you know you're in the enterprise. It's what happens when you don't have a plan.