People say that there isn't any age discrimination in aviation, and while I've no reason to suspect otherwise, i think I'd consider the actual practical implications of being 30.
I'm 21 and about to start post PPL. I'm pretty much writing off the next 10 years in terms of earning potential. It could be that long before I even get into the right hand seat of a jet. Seniority takes a while in aviation so I've heard.
So while you'd have no disadvantage actually getting each job in terms of discrimination, I'd be absolutely sure you're ok starting right at the beginning at age 30. I don't know what your personal circumstances are but are you ok having a low earning potential until you're perhaps 40?