30s are the apt time when you really tend to learn from your 20s. There are many things that you have learn about entering and living in 30s.
You do not need to figure it out on the whole
At a younger stage in life you would have thought that by the time you reach 30, you would be able to figure out everything in life. Some people were lucky enough to figure things out early in their lives, but most people are still clueless. And, it's fine. There's still plenty of time.
You have a bigger bank balance
You should have savings. So that you no longer have to depend from salary to salary.
Stop taking your family for granted
When you were young, you always tend to assume that your immediate family members would be there for you, whatever happens. Knowing your siblings and parents more as an adult will definitely be a fulfilling experience on the whole.
Fitness plays an important part in your life
During younger age the importance of doing exercise would be minimal and you do not seem to take it seriously. Being fit and active not only grants you with good health and longer life but also boosts up your self esteem.
You've learned to love yourself
Insecurity and doubt will probably never go away. But, you're settling into the person you're meant to be, and you're a lot more accepting of that person and have even started to love that person.