I absolutely love this question!
In life seek happiness. Life is short and you need to make the most of it.
First I would like to state that I agree with the philosopher Dag.
You are the only one who can answer this question as it is individual for all of us.
Experiences enrich your life.
I'm in the over 50 crowd (although not but much) and have a lot to say about success and how to measure it. I was raised to grow up, work hard, save for retirement and "be successful". In my family success was measure by money and position or power. I did all those things and have been successful in my career. For the most part I have enjoyed my chosen path and have been content if not happy the majority of the time. However, with that said---in my career I've had times when I wondered "is this all there is." When you are building a career there are times when it is not as fulfilling as others. (personal opinion)..... my belief is that is why they call it work and not vacation.
Years ago I told my husband that my goal was to take a year off and travel the world before I was 50.... he laughed--- but I set the goal, began to save and that is exactly what we did. It was a magnificent experience. I cannot explain the way it has enriched and changed our lives.
But it has also made us restless and we are no longer as content doing what we were doing before our travels. The flip side to that is that we earn enough money to travel to exotic lands (when we can get off work) Looking around at friends who have lost their homes, lost their jobs, lost their savings --- I am grateful to be in my chosen field because it provides stability.
I think it is good that you have had an opportunity to compare yourself to friends----- I believe that reflection and self evaluation is vital. You may come to a cross roads when "you" want to do something different. Only you will know. Just because you take one path does not mean you need to stay on that path your entire life.
I have re-invented myself several times and it keeps me fresh.
For me, I needed financial stability and I have that......and now it allows me to travel. I personally didn't want to end up 80 years old and not have a roof over my head.
We took the trip around the world because I didn't want to be 80 years old and ask why I spent my entire life focused on my career and didn't do some travel. I did not want to have regrets.
I agree that success needs to be defined by you and not society. I found my balance and I'm certain you can find yours.