I'm not actually that young, I'm 33.

That is young. Health effects (for many things) show up much later, past 50 or even 60. Until then most bodies can compensate for quite a lot of stuff that has gone wrong earlier.

If you take cancer rates by age as an indicator you can see age 33 barely registers: https://canceraustralia.gov.au/sites/default/files/statistic...

Or diabetes: http://www.cdc.gov/diabetes/statistics/age/fig1.gif