People treat the big 3-0 like this big miraculous age where everything in life will change; after thirty it will be acceptable - expected even - to get more serious about life. But in all actuality there are some of us who are serious about life at our current ages. Thirty is not the be all end all when it comes to deciding you are ready to adopt an adult mindset. Knowledge, maturity and growth should be something we build on with each coming year, instead of waiting for a false beacon of light that being thirty brings. I know people that are still doing the same things at 27 that they were doing at 24, so to assume that the bridge between 29 and 30 will bring about some grand 'a-ha' moment seems trivial.
Don't allow people to tell you you're too young for something, or too old for something. You decide. There's no one age where things will be just right all across the board. You decide your pace. Set your own timeline.