Dear Starter, I can comprehend your feeling as I'm 34 years old and, after 7 years working experience in dairy field, I would like to start PhD studies too. An Irish Postdoc told me that, even I'm a little older than many of the students applying for postgraduates studie, I have the experience often lacking in them. Knowing how to plan, perform, realize and publish research projects is a great advantages on my side that younger workers don't have. So feel confident you will get the goal.