The fact that you gave up the first time just means you weren't ready for the commitment at that point in your life. And if you weren't ready but did go through with it, it wouldn't have been a success anyway.
You first had to become the person you are now in order to be able to use SteemIt to grow. Time will tell if it's the right time for you.
Being a Steemian indeed requires a lot of dedication, time and effort. It's not just a matter of 'wanting' to put in these things, but more about being able to, and being ready to do it.
To become successful on Steemit, you first have to go through personal growth, because once you're on here, you'll have to deal with feelings like frustration and failure. You've got to grow and find believe in yourself before you can turn SteemIt into a success.
So don't beat yourself up about leaving the first time. See your comeback as prove for the fact that you've grown as a person that is now ready to cope with all the difficulties SteemIt will present you. Actually, you should congratulate yourself, because most people don't grow at all in their lives, they don't improve. But you.. you did!